ajax xhr lengthComputable用php文件返回false

Question

我正在使用XMLHttpRequest执行ajax请求以显示请求的进度.它与html文件一起运行很好但是evt.lengthComputable用php文件返回false.

我的php文件以utf-8编码,没有任何特殊之处.

                xhr: function()
            {

              console.log('xhr');
              var xhr = new XMLHttpRequest();


              xhr.addEventListener('loadend', uploadComplete, false);
              function uploadComplete(event) {
                  console.log('uploadComplete');
                  //do stuff
              }


              //Download progress
              xhr.addEventListener("progress", function(evt){
                console.log([evt.lengthComputable, evt.loaded, evt.total]);
                if (evt.lengthComputable) {
                  var percentComplete = (evt.loaded / evt.total) * 100;


                }
              }, false);
              return xhr;
            }

Thanx帮助:)!

Answer 1

因为php文件是动态的,所以需要设置正确的Content-Length标头:

<?
ob_start();
/* your code here */

$length = ob_get_length();
header('Content-Length: '.$length."\r\n");
header('Accept-Ranges: bytes'."\r\n");
ob_end_flush();