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• 句法
• 范例
• 规范
• 浏览器兼容性
• 相关话题

connectStart read-only property returns the timestamp immediately before the user agent starts establishing the connection to the server to retrieve the resource.

注意： 此特征可用于 Web 工作者 .

句法

resource.connectStart;
					

返回值

A DOMHighResTimeStamp immediately before the browser starts to establish the connection to the server to retrieve the resource.

范例

In the following example, the value of the *Start and *End properties of all " resource " type events are logged.

function print_PerformanceEntries() {
  // Use getEntriesByType() to just get the "resource" events
  var p = performance.getEntriesByType("resource");
  for (var i=0; i < p.length; i++) {
    print_start_and_end_properties(p[i]);
  }
}
function print_start_and_end_properties(perfEntry) {
  // Print timestamps of the PerformanceEntry *start and *end properties
  properties = ["connectStart", "connectEnd",
                "domainLookupStart", "domainLookupEnd",
                "fetchStart",
                "redirectStart", "redirectEnd",
                "requestStart",
                "responseStart", "responseEnd",
                "secureConnectionStart"];
  for (var i=0; i < properties.length; i++) {
    // check each property
    var supported = properties[i] in perfEntry;
    if (supported) {
      var value = perfEntry[properties[i]];
      console.log("... " + properties[i] + " = " + value);
    } else {
      console.log("... " + properties[i] + " = NOT supported");
    }
  }
}
					

规范

规范	状态	注释
Resource Timing Level 1 The definition of 'connectStart' in that specification.	候选推荐	初始定义。

浏览器兼容性

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
connectStart	Chrome 43	Edge 12	Firefox 40	IE 10	Opera 32	Safari 11	WebView Android 43	Chrome Android 43	Firefox Android 42	Opera Android 32	Safari iOS 11	Samsung Internet Android 4.0

图例

完整支持

完整支持

元数据

• 最后修改： 2020 年 1 月 22 日

相关话题

1. 资源计时 API
2. PerformanceResourceTiming
3. 特性

   1. connectEnd
   2. connectStart
   3. decodedBodySize
   4. domainLookupEnd
   5. domainLookupStart
   6. encodedBodySize
   7. fetchStart
   8. initiatorType
   9. nextHopProtocol
   10. redirectEnd
   11. redirectStart
   12. requestStart
   13. responseEnd
   14. responseStart
   15. secureConnectionStart
   16. serverTiming
   17. transferSize
   18. workerStart
4. 方法

   1. toJSON()
5. 继承：

   1. PerformanceEntry
6. Related pages for Resource Timing API

   1. 性能
   2. PerformanceEntry
   3. Window.performance