如下js代码，openProgressBar函数通过ajax，定时请求后端服务。我发现 ie7好用 chrome就不行。 ==============================code=============================== interval = null; function openProgressBar() { /* generate random progress-id */ uuid = ""; for (i = 0; i < 32; i++) { uuid += Math.floor(Math.random() * 16).toString(16); } /* patch the form-action tag to include the progress-id */ document.getElementById("upload").action="/upload.php?X-Progress-ID=" + uuid; /* call the progress-updater every 1000ms */ interval = window.setInterval( function () { fetch(uuid); }, 1000 ); } function fetch(uuid) { req = new XMLHttpRequest(); req.open("GET", "/progress", 1); req.setRequestHeader("X-Progress-ID", uuid); req.onreadystatechange = function () { if (req.readyState == 4) { if (req.status == 200) { /* poor-man JSON parser */ var upload = eval(req.responseText); document.getElementById('tp').innerHTML = upload.state; /* change the width if the inner progress-bar */ if (upload.state == 'done' || upload.state == 'uploading') { bar = document.getElementById('progressbar'); w = 400 * upload.received / upload.size; bar.style.width = w + 'px'; } /* we are done, stop the interval */ if (upload.state == 'done') { window.clearTimeout(interval); } } } } req.send(null); }