W3C

Resource Timing

W3C Candidate Recommendation 22 May 2012

This version:
http://www.w3.org/TR/2012/CR-resource-timing-20120522/
Latest version:
http://www.w3.org/TR/resource-timing/
Latest Editor's Draft:
http://www.w3c-test.org/webperf/specs/ResourceTiming/
Previous versions:
http://www.w3.org/TR/2011/WD-resource-timing-20110811/
Editors:
Jatinder Mann, Microsoft Corp.,
Zhiheng Wang, Google Inc.,
Anderson Quach, Microsoft Corp. (Until March 2011)

Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.

Abstract

This specification defines an interface for web applications to access the complete timing information for resources in a document.

Status of this document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.

W3C publishes a Candidate Recommendation to indicate that the document is believed to be stable and to encourage implementation by the developer community.

The entrance criteria for this document to enter the Proposed Recommendation stage is to have a minimum of two independent and interoperable user agents that implementation all the features of this specification, which will be determined by passing the user agent tests defined in the test suite developed by the Working Group.

The Working Group does not expect to advance to Proposed Recommendation prior to . A preliminary implementation report is available and will be updated during the Candidate Recommendation period. This is a work in progress and may change without any notices.

The Working Group intends to gain implementation experience before recommending implementations to remove their vendor prefixes.

Please send comments to public-web-perf@w3.org (archived) with [ResourceTiming] at the start of the subject line by .

A diff document with the previous draft is available.

This document is produced by the Web Performance Working Group. The Web Performance Working Group is part of the Rich Web Clients Activity in the W3C Interaction Domain.

You can find the latest Editor's Draft of this document in the W3C's Mercurial repository, which is updated on a regular basis.

Publication as a Candidate Recommendation does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

Table of Contents

  1. 1 Introduction
  2. 2 Conformance requirements
  3. 3 Terminology
  4. 4 Resource Timing
    1. 4.1 Introduction
    2. 4.2 Resources Included in the PerformanceResourceTiming Interface
    3. 4.3 The PerformanceResourceTiming Interface
    4. 4.4 The Resource Timing Methods
    5. 4.5 Cross-origin Resources
    6. 4.6 Vendor Prefixes
  5. 5 Process
    1. 5.1 Processing Model
    2. 5.2 Monotonic Clock
  6. 6 Privacy and Security
  7. Acknowledgements
  8. References

1 Introduction

This section is non-normative.

User latency is an important quality benchmark for Web Applications. While JavaScript-based mechanisms can provide comprehensive instrumentation for user latency measurements within an application, in many cases, they are unable to provide a complete end-to-end latency picture. While Navigation Timing [NavigationTiming] addresses part of the problem by providing timing information associated with a navigation, this document introduces the ResourceTiming interface to allow JavaScript mechanisms to collect complete timing information related to resources on a document.

For example, the following JavaScript shows a simple attempt to measure the time it takes to fetch a resource:

<!doctype html>
<html>
  <head>
  </head>
  <body onload="loadResources()">
    <script>
        function loadResources() 
        {
           var start = new Date().getTime();
           var image1 = new Image();
           image1.src = 'http://w3c-test.org/webperf/image1.png';
           image1.onload = resourceTiming;

           var resourceTiming = function() {
               var now = new Date().getTime();
               var latency = now - start;
               alert("End to end resource fetch: " + latency);
           };
        } 
    </script>
    <img src="http://w3c-test.org/webperf/image0.png">
  </body>
</html>

Though this script can measure the time it takes to fetch a resource, it cannot break down the time spent in various phases. Further, the script cannot easily measure the time it takes to fetch resources described in markup.

To address the need for complete information on user experience, this document introduces the PerformanceResourceTiming interface. This interface allows JavaScript mechanisms to provide complete client-side latency measurements within applications. With this interface, the previous example can be modified to measure a user's perceived load time of a resource.

The following script calculates the amount of time it takes to fetch every resource in the page, even those defined in markup. This example assumes that this page is hosted on http://w3c-test.org. One could further measure the amount of time it takes in every phase of fetching a resource with the PerformanceResourceTiming interface. 

<!doctype html>
<html>
  <head>
  </head>
  <body onload="loadResources()">
    <script>
       function loadResources() 
       {
          var image1 = new Image();
          image1.src = 'http://w3c-test.org/webperf/image1.png';
          image1.onload = resourceTiming;
       }
       
       function resourceTiming() 
       {
           var resourceList = window.performance.getEntriesByType("resource");
           for (i = 0; i < resourceList.length; i++)
           {
              if (resourceList[i].initiatorType == "img") 
              {
                 alert("End to end resource fetch: "+ resourceList[i].responseEnd - resourceList[i].startTime);
              }
           }
       }
    </script>
    <img id="image0" src="http://w3c-test.org/webperf/image0.png">
  </body>
</html>

2 Conformance requirements

All diagrams, examples, and notes in this specification are non-normative, as are all sections explicitly marked non-normative. Everything else in this specification is normative.

The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in the normative parts of this document are to be interpreted as described in RFC2119. For readability, these words do not appear in all uppercase letters in this specification. [RFC2119]

Requirements phrased in the imperative as part of algorithms (such as "strip any leading space characters" or "return false and abort these steps") are to be interpreted with the meaning of the key word ("must", "should", "may", etc) used in introducing the algorithm.

Some conformance requirements are phrased as requirements on attributes, methods or objects. Such requirements are to be interpreted as requirements on user agents.

Conformance requirements phrased as algorithms or specific steps may be implemented in any manner, so long as the end result is equivalent. (In particular, the algorithms defined in this specification are intended to be easy to follow, and not intended to be performant.)

The IDL fragments in this specification must be interpreted as required for conforming IDL fragments, as described in the Web IDL specification. [Web IDL]

3 Terminology

The construction "a Foo object", where Foo is actually an interface, is sometimes used instead of the more accurate "an object implementing the interface Foo".

The term DOM is used to refer to the API set made available to scripts in Web applications, and does not necessarily imply the existence of an actual Document object or of any other Node objects as defined in the DOM Core specifications. [DOM3CORE]

A DOM attribute is said to be getting when its value is being retrieved (such as by author script), and is said to be setting when a new value is assigned to it.

The term "JavaScript" is used to refer to ECMA262, rather than the official term ECMAScript, since the term JavaScript is more widely known. [ECMA262]

4 Resource Timing

4.1 Introduction

This section is non-normative.

The PerformanceResourceTiming interface facilitates timing measurement of downloadable resources on the root page. It represents the timing information related to resources that initiate network downloads. For example, this interface is available for XMLHttpRequest objects [XMLHttpRequest], HTML elements [HTML5] such as iframe, img, script, object, audio, video, embed, and link with the link type of stylesheet, and SVG elements [SVG] such as svg.

The term "resource" is also used to refer to these elements in this work.

4.2 Resources Included in the PerformanceResourceTiming Interface

The PerformanceResourceTiming interface must include all resources fetched from the networking layer by the current browsing context. Resources that are retrieved from the user agent's networking layer cache must be included in the PerformanceResourceTiming interface.

The rest of this section is non-normative.

Examples:

The user agent may choose to limit how many resources are included in the PerformanceResourceTiming interface. The recommended minimum number of resources is 150, though this may be changed by the user agent. setResourceTimingBufferSize can be called to request a change to this limit.

4.3 The PerformanceResourceTiming Interface

interface PerformanceResourceTiming : PerformanceEntry {
  readonly attribute DOMString initiatorType; 
  // "css", "embed", "img", "link", "object", "script", "subdocument", "svg", "xmlhttprequest", "other"
  
  readonly attribute DOMHighResTimeStamp redirectStart;
  readonly attribute DOMHighResTimeStamp redirectEnd;
  readonly attribute DOMHighResTimeStamp fetchStart;
  readonly attribute DOMHighResTimeStamp domainLookupStart;
  readonly attribute DOMHighResTimeStamp domainLookupEnd;
  readonly attribute DOMHighResTimeStamp connectStart;
  readonly attribute DOMHighResTimeStamp connectEnd;
  readonly attribute DOMHighResTimeStamp secureConnectionStart;
  readonly attribute DOMHighResTimeStamp requestStart;
  readonly attribute DOMHighResTimeStamp responseStart;
  readonly attribute DOMHighResTimeStamp responseEnd;
};

The PerformanceResourceTiming interface participates in the Performance Timeline and extends the following attributes of the PerformanceEntry interface:

The name attribute must return the resolved URL of the requested resource. This attribute must not change even if the fetch redirected to a different URL.

The entryType attribute must return the DOMString resource.

The startTime attribute must return a DOMHighResTimeStamp with the time immediately before the user agent starts to queue the resource for fetching. If there are HTTP redirects or equivalent when fetching the resource, and if all the redirects or equivalent are from the same origin as the current document or the Timing-Allow-Origin HTTP response header rules are met, this attribute must return the same value as redirectStart. Otherwise, this attribute must return the same value as fetchStart.

The duration attribute must return a DOMHighResTimeStamp equal to the difference between responseEnd and startTime, respectively.

initiatorType attribute

On getting, the initiatorType IDL attribute must one of the following DOMStrings representing the type of object that initiated the request for the resource:

redirectStart attribute

If there are HTTP redirects or equivalent when fetching the resource and if all the redirects or equivalent are from the same origin as the current document, this attribute must return the starting time of the fetch that initiates the redirect.

If there are HTTP redirects or equivalent when fetching the resource and if any of the redirects are not from the same origin as the current document, and the Timing-Allow-Origin HTTP response header rules are met, this attribute must return the starting time of the fetch that initiates the redirect. Otherwise, this attribute must return zero.

redirectEnd attribute

If there are HTTP redirects or equivalent when fetching the resource and if all the redirects or equivalent are from the same origin as the current document, this attribute must return the time immediately after receiving the last byte of the response of the last redirect.

If there are HTTP redirects or equivalent when fetching the resource and if any of the redirects are not from the same origin as the current document, and the Timing-Allow-Origin HTTP response header rules are met, this attribute must return the time immediately after receiving the last byte of the response of the last redirect. Otherwise, this attribute must return zero.

fetchStart attribute

If there are no HTTP redirects or equivalent, this attribute must return the time immediately before the user agent starts to fetch the resource.

If there are HTTP redirects or equivalent, this attribute must return the time immediately before the user agent starts to fetch the final resource in the redirection.

domainLookupStart attribute

This attribute must return the time immediately before the user agent starts the domain name lookup for the resource. If a persistent connection [RFC 2616] is used or the resource is retrieved from relevant application caches or local resources, this attribute must return the same value as fetchStart.

If the last non-redirected fetch of the resource is not the same origin as the current document, domainLookupStart must return zero unless the Timing-Allow-Origin HTTP response header rules apply.

domainLookupEnd attribute

This attribute must return the time immediately after the user agent finishes the domain name lookup for the resource. If a persistent connection [RFC 2616] is used or the resource is retrieved from relevant application caches or local resources, this attribute must return the same value as fetchStart.

If the user agent has the domain information in cache, domainLookupStart and domainLookupEnd represent the times when the user agent starts and ends the domain data retrieval from the cache.

If the last non-redirected fetch of the resource is not the same origin as the current document, domainLookupEnd must return zero unless the Timing-Allow-Origin HTTP response header rules apply.

connectStart attribute

This attribute must return the time immediately before the user agent start establishing the connection to the server to retrieve the resource. If a persistent connection [RFC 2616] is used or the resource is retrieved from relevant application caches or local resources, this attribute must return value of domainLookupEnd.

If the last non-redirected fetch of the resource is not the same origin as the current document, connectStart must return zero unless the Timing-Allow-Origin HTTP response header rules apply.

connectEnd attribute

This attribute must return the time immediately after the user agent finishes establishing the connection to the server to retrieve the resource. If a persistent connection [RFC 2616] is used or the resource is retrieved from relevant application caches or local resources, this attribute must return the value of domainLookupEnd.

If the transport connection fails and the user agent reopens a connection, connectStart and connectEnd should return the corresponding values of the new connection.

connectEnd must include the time interval to establish the transport connection. It must not include other time interval such as SSL handshake and SOCKS authentication.

If the last non-redirected fetch of the resource is not the same origin as the current document, connectEnd must return zero unless the Timing-Allow-Origin HTTP response header rules apply.

secureConnectionStart attribute

This attribute is optional. User agents that don't have this attribute available must set it as undefined. When this attribute is available, if the scheme of the current page is HTTPS, this attribute must return the time immediately before the user agent starts the handshake process to secure the current connection. If the secureConnectionStart attribute is available but HTTPS is not used, this attribute must return zero.

If the last non-redirected fetch of the resource is not the same origin as the current document, secureConnectionStart must return zero unless the Timing-Allow-Origin HTTP response header rules apply.

requestStart attribute

This attribute must return the time immediately before the user agent starts requesting the resource from the server, or from relevant application caches or from local resources.

If the transport connection fails after a request is sent and the user agent reopens a connection and resend the request, requestStart must return the corresponding values of the new request.

If the last non-redirected fetch of the resource is not the same origin as the current document, requestStart must return zero unless the Timing-Allow-Origin HTTP response header rules apply.

responseStart attribute

This attribute must return the time immediately after the user agent receives the first byte of the response from the server, or from relevant application caches or from local resources.

If the last non-redirected fetch of the resource is not the same origin as the current document, responseStart must return zero unless the Timing-Allow-Origin HTTP response header rules apply.

responseEnd attribute

This attribute must return the time immediately after the user agent finishes receiving the last byte of the resource from from relevant application caches or from local resources.

4.4 The Resource Timing Methods

partial interface Performance {
  void clearResourceTimings();
  void setResourceTimingBufferSize(unsigned long maxSize);

  attribute Function onresourcetimingbufferfull;
};

clearResourceTimings method

The method clearResourceTimings clears the buffer used to store the current list of PerformanceResourceTiming resources.

No parameters

No return value

No additional exceptions

setResourceTimingBufferSize method

The setResourceTimingBufferSize method, when invoked, must set the maximum number of PerformanceResourceTiming resources that may be stored in the buffer to the value of the maxSize parameter.

If this method is not called, the user agent should store at least 150 PerformanceResourceTiming resources in the buffer, unless otherwise specified by the user agent.

if the maxSize parameter is less than the number of elements currently stored in the buffer, no elements in the buffer are to be removed. The maxSize parameter will apply only after the clearResourceTimings method is called.

Parameters

in maxSize type of unsigned long

The maxSize parameter sets the maximum number of PerformanceResourceTiming resources that will be stored in the buffer.

No return value

No additional exceptions

onresourcetimingbufferfull attribute

The callback onresourcetimingbufferfull is triggered when the buffer used to store the list of PerformanceResourceTiming is full. The callback can be used to package existing PerformanceResourceTiming resources and clear the buffered PerformanceResourceTiming list. While executing the onresourcetimingbufferfull callback, PerformanceResourceTiming will continue to be collected beyond the maximum limit of the resources allowed in the PerformanceResourceTiming interface until one of the following occurs:

  1. clearResourceTimings is called - The PerformanceEntryList will begin with the n+1th item if it exists and the first n elements are released, where n is the maximum number of resources allowed in the PerformanceResourceTiming interface. If the n+1th item does not exist, the buffer is cleared. The max length of the PerformanceEntryList does not change unless otherwise specified by setResourceTimingBufferSize.
  2. setResourceTimingBufferSize is called - The PerformanceEntryList will extend and / or truncate to the buffer size specified.
  3. Neither clearResourceTimings or setResourceTimingBufferSize is called during the execution of the onresourcetimingbufferfull callback - no updates are made to the PerformanceEntryList.

4.5 Cross-origin Resources

Information from cross-origin resources must be included in the PerformanceResourceTiming interface. In the absence of the Timing-Allow-Origin HTTP response header, these attributes must be set to zero: redirectStart, redirectEnd, domainLookupStart, domainLookupEnd, connectStart, connectEnd, requestStart, responseStart and secureConnectionStart, if supported by the user agent.

The terms origin and same origin are defined by The HTTP Origin Header. [IETF RFC 6454]

The term cross-origin is used to mean non same origin.

Server-side applications may return the Timing-Allow-Origin HTTP response header to allow the User Agent to fully expose, to the document origin(s) specified, the values of attributes that would have been zero due to the cross-origin restrictions previously specified in this section.

Timing-Allow-Origin Response Header

The Timing-Allow-Origin header indicates whether a resource's timing can be shared based by returning the value of the Origin request header in the response. ABNF:

Timing-Allow-Origin = "Timing-Allow-Origin" ":" origin-list-or-null | "*"

origin-list-or-null is defined by The HTTP Origin Header. [IETF RFC 6454]

4.6 Vendor Prefixes

Vendor-specific proprietary user agent extensions are discouraged. If such extensions are needed, e.g., for experimental purposes, vendors must use the following extension mechanisms:

If an extension to the initiatorType IDL attribute return value is needed for an experimental initiator type, on getting the initiatorType IDL attribute, vendors MUST return a DOMString that uses the following convention:

[vendorprefix]-[name]

Where,

If the extension is a new timing attribute, it must:

5 Process

5.1 Processing Model

Illustration

This section is non-normative.

The following graph illustrates the timing attributes defined by the PerformanceResourceTiming interface. Attributes underlined may not be available when fetching resources from different origins. User agents may perform internal processing in between timings, which allow for non-normative intervals between timings.

Resource Timing attributes

  1. Once the Window object of the current document is created, the user agent must create a PerformanceEntryList primary buffer object to store the list of PerformanceResourceTiming resources.
  2. Set the primary buffer to a size of 150, unless otherwise specified by the user agent or set by the setResourceTimingBufferSize method.
  3. For each resource fetched by the current browsing context, perform the following steps:
    1. Create a new PerformanceResourceTiming object and set entryType to the DOMString resource.
    2. Immediately before the user agent starts to queue the resource for retrieval, record the current time in startTime.
    3. Record the initiator of the resource in initiatorType.
    4. Record the resolved URL of the requested resource in name.
    5. If the new resource is to be fetched using HTTP GET or equivalent, immediately before a user agent checks with the relevant application caches, record the current time as fetchStart. Otherwise, immediately before a user agent starts the fetching process, record the current time as fetchStart. Let domainLookupStart, domainLookupEnd, connectStart and connectEnd be the same value as fetchStart.
    6. If the resource is not to be fetched from the networking layer, such as being fetched from an in-memory cache, abort the remaining steps.
    7. If fetching the resource is aborted for any reason, abort the remaining steps.
    8. If the last non-redirected fetch of the resource is not the same origin as the current document and the Timing-Allow-Origin HTTP response header does not apply, the user agent must set redirectStart, redirectEnd, domainLookupStart, domainLookupEnd, connectStart, connectEnd, requestStart, responseStart and secureConnectionStart, if supported by the user agent, to zero and go to Step 3.17.
    9. Let domainLookupStart, domainLookupEnd, connectStart and connectEnd be the same value as fetchStart.
    10. If the resource is fetched from the relevant application cache or local resources, including the HTTP cache, go to step 3.15.
    11. If no domain lookup is required, go to step 3.13. Otherwise, immediately before a user agent starts the domain name lookup, record the time as domainLookupStart.
    12. Record the time as domainLookupEnd immediately after the domain name lookup is successfully done. A user agent may need multiple retries before that. If the domain lookup fails, abort the remaining steps.
    13. If a persistent transport connection is used to fetch the resource, let connectStart and connectEnd be the same value of domainLookupEnd. Otherwise, record the time as connectStart immediately before initiating the connection to the server and record the time as connectEnd immediately after the connection to the server or the proxy is established. A user agent may need multiple retries before this time. If a connection can not be established, abort the remaining steps.
    14. If the user agent supports the secureConnectionStart attribute, in step 3.13, a user agent should also carry out these additional steps:
      1. If the scheme of the current resource is HTTPS, the user agent must record the time as secureConnectionStart immediately before the handshake process to secure the connection.
      2. If the scheme of the current resource is not HTTPS, the user agent must set the value of secureConnectionStart to 0.
    15. Immediately before a user agent starts sending the request for the resource, record the current time as requestStart.
    16. Record the time as responseStart immediately after the user agent receives the first byte of the response.
    17. Record the time as responseEnd immediately after receiving the last byte of the response.

      Return to step 3.13 if the user agent fails to send the request or receive the entire response, and needs to reopen the connection.

      Example

      When persistent connection [RFC 2616] is enabled, a user agent may first try to re-use an open connect to send the request while the connection can be asynchronously closed. In such case, connectStart, connectEnd and requestStart should represent timing information collected over the re-open connection.

    18. Record the difference between responseEnd and startTime in duration.
    19. If the fetched resource results in an HTTP redirect or equivalent, then
      1. If the current resource and the resource that is redirected to are not from the same origin, set redirectStart and redirectEnd to 0. Then, return to step 3.5 with the new resource.
      2. If the value of redirectStart is not set, let it be the value of fetchStart.
      3. Let redirectEnd be the value of responseEnd.
      4. Set all the attributes in the PerformanceResourceTiming object to 0 except startTime, redirectStart, and redirectEnd, initiatorType.
      5. Return to step 3.5 with the new resource.
    20. If the primary buffer is full, the callback onresourcetimingbufferfull must be triggered.
      1. Create a temporary buffer of PerformanceResourceTiming objects.
      2. Add the current resource to the temporary buffer.
      3. If there are additional resources that are collected during the onresourcetimingbufferfull callback, add them to the temporary buffer.
      4. If the clearResourceTimings method is called in the onresourcetimingbufferfull callback, clear all PerformanceResourceTiming objects in the primary buffer. Copy all PerformanceResourceTiming objects in the temporary buffer to the primary buffer.
      5. If the setResourceTimingBufferSize method is called in the onresourcetimingbufferfull callback, set the maximum size of the primary buffer to the maxSize parameter. If the maxSize parameter is larger than the previous size of the primary buffer, append PerformanceResourceTiming objects in the temporary buffer to the primary buffer up to the maxSize parameter.
      6. Discard the temporary buffer.
    21. If the primary buffer is not full, add the PerformanceResourceTiming object, created in step 3.1, to the primary buffer.

5.2 Monotonic Clock

The value of the timing attributes must monotonically increase to ensure timing attributes are not skewed by adjustments to the system clock while fetching the resource. The difference between any two chronologically recorded timing attributes must never be negative. For all resources, including subdocument resources, the user agent must record the system clock at the beginning of the root document navigation and define subsequent timing attributes in terms of a monotonic clock measuring time elapsed from the beginning of the navigation.

6 Privacy and Security

This section is non-normative.

The PerformanceResourceTiming interface exposes timing information for a resource to any web page that has included that resource. To limit the access to the PerformanceResourceTiming interface, the same origin policy is enforced by default and certain attributes are set to zero, as described in Section 4.5 Cross-origin Resources. Resource providers can explicitly allow all timing information to be collected for a resource by adding the Timing-Allow-Origin HTTP response header, which specifies the domains that are allowed to access the timing information.

Statistical fingerprinting is a privacy concern where a malicious web site may determine whether a user has visited a third-party web site by measuring the timing of cache hits and misses of resources in the third-party web site. Though the PerformanceResourceTiming interface gives timing information for resources in a document, the cross-origin restrictions prevent making this privacy concern any worse than it is today using the load event on resources to measure timing to determine cache hits and misses.

Acknowledgements

We would like to sincerely thank Karen Anderson, Darin Fisher, Tony Gentilcore, Nic Jansma, Arvind Jain, Kyle Scholz, Jonas Sicking, James Simonsen, Steve Souders, Annie Sullivan, Sigbjørn Vik, Jason Weber to acknowledge their contributions to this work.

References

[IETF RFC 2119]
Key words for use in RFCs to Indicate Requirement Levels, Scott Bradner, Author. Internet Engineering Task Force, March 1997. Available at http://www.ietf.org/rfc/rfc2119.txt.
[IETF RFC 2616]
Hypertext Transfer Protocol -- HTTP/1.1, R. Fielding et al., Authors. Internet Engineering Task Force, June 1999. Available at http://www.ietf.org/rfc/rfc2616.txt.
[IETF RFC 6454]
The Web Origin Concept, Adam Barth, Author. Internet Engineering Task Force, December 2011. Available at http://www.ietf.org/rfc/rfc6454.txt.
[DOM Level 3 Core]
Document Object Model Level 3 Core Specification, A. Le Hors, et al., Editors. World Wide Web Consortium, 7 April 2004. This version of the Document Object Model Level 3 Core Recommendation is http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407. The latest version of DOM4 is available at http://www.w3.org/TR/dom/.
[ECMA-262]
ECMAScript Language Specification, 5.1 Edition. ECMA International, Standard ECMA-262, June 2011. This version of the ECMAScript Language is available from http://www.ecma-international.org/publications/standards/Ecma-262.htm.
[XMLHttpRequest]
XMLHttpRequest, Anne van Kesteren, Editor. World Wide Web Consortium, January 2012. This version of the XMLHttpRequest specification is http://www.w3.org/TR/2012/WD-XMLHttpRequest-20120117/. The latest version of XMLHttpRequest is available at http://www.w3.org/TR/XMLHttpRequest/.
[HTML5]
HTML5, Ian Hickson, Editor. World Wide Web Consortium, March 2012. This version of the HTML5 is available from http://www.w3.org/TR/html5/. The latest editor's draft is available at http://dev.w3.org/html5/spec/.
[SVG]
Scalable Vector Graphics (SVG) 1.1, Erik Dahlström, et al, Editors. World Wide Web Consortium, August 2011. This version of the SVG specification Recommendation is available from http://www.w3.org/TR/2011/REC-SVG11-20110816/. The latest version of SVG is available at http://www.w3.org/TR/SVG/.
[Navigation Timing]
Navigation Timing, Zhiheng Wang, Editor. World Wide Web Consortium, March 2012. This version of the Navigation Timing specification is available from http://www.w3.org/TR/2012/CR-navigation-timing-20120313/. The latest version of Navigation Timing is available at http://www.w3.org/TR/navigation-timing/.
[Performance Timeline]
Performance Timeline, Jatinder Mann, et al, Editors. World Wide Web Consortium, May 2012. This version of the Performance Timeline specification is available from http://www.w3.org/TR/2012/WD-performance-timeline-20120508/. The latest version of Performance Timeline is available at http://www.w3.org/TR/performance-timeline/.
[High Resolution Time]
High Resolution Time, Jatinder Mann, Editor. World Wide Web Consortium, May 2012. This version of the High Resolution Time specification is available from http://www.w3.org/TR/2012/WD-hr-time-20120522/. The latest version of High Resolution Time is available at http://www.w3.org/TR/hr-time/.
[Web IDL]
Web IDL, Cameron McCormack, Editor. World Wide Web Consortium, April 2012. This version of the Web IDL specification is available from http://www.w3.org/TR/2012/CR-WebIDL-20120419/. The latest version of Web IDL is available at http://www.w3.org/TR/WebIDL/.