requestStart
只读特性返回
timestamp
of the time immediately before the browser starts requesting the resource from the server, cache, or local resource. If the transport connection fails and the browser retires the request, the value returned will be the start of the retry request.
There is no
end
property for
requestStart
.
resource.requestStart;
A
DOMHighResTimeStamp
representing the time immediately before the browser starts requesting the resource from the server
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 | 状态 | 注释 |
|---|---|---|
|
Resource Timing Level 1
The definition of 'requestStart' in that specification. |
候选推荐 | 初始定义。 |
| 桌面 | 移动 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
requestStart
|
Chrome 43 | Edge 12 | Firefox 40 | IE 不支持 No | Opera 30 | Safari 11 | WebView Android 43 | Chrome Android 43 | Firefox Android 42 | Opera Android 30 | Safari iOS 11 | Samsung Internet Android 4.0 |
完整支持
不支持
PerformanceResourceTiming