XMLHttpRequestEventTarget.onloadstart - Web APIs 编辑

The XMLHttpRequestEventTarget.onloadstart is the function called when an XMLHttpRequest transaction starts transferring data.

Syntax

XMLHttpRequest.onloadstart = callback;

Values

• callback is the function to be called when the transaction begins to transfer data.

Example

var xmlhttp = new XMLHttpRequest(),
  method = 'GET',
  url = '/wiki/';

xmlhttp.open(method, url, true);
xmlhttp.onloadstart = function () {
  console.log("Download underway");
};
xmlhttp.send();

Specifications

Browser compatibility

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