有时候需要显示进度，这时候就需要做一些切割，具体上传代码如下：
<!DOCTYPE HTML> <html lang="en-US"> <head> <meta charset="UTF-8"> <title></title> <script src="http://cdn.bootcss.com/jquery/2.2.4/jquery.js"></script> </head> <body> <input type="file" name="my_big_file" id="my_big_file" /> <input type="button" value="上传" id="upload_btn" /> <div id="tip"></div> <script type="text/javascript"> $(function(){ //页面加载完毕后开始执行的事件 $("#upload_btn").click(function(){ if($("#my_big_file").val()=="") { console.log("请选择文件");return false; } var file= document.getElementById("my_big_file").files[0]; var total_size=file.size; var step=1024*1024; var num=Math.ceil(total_size/step); var has_loaded=0; for(var i=0;i<num;i++) { has_loaded+=step; //var reader= new FileReader(); //reader.readAsBinaryString(file.slice(has_loaded,has_loaded+step)); $("#tip").html("当前进度 "+has_loaded/total_size*100+"%"); sleep(10); console.log("当前进度 "+has_loaded/total_size*100+"%"); //reader.onprogress=function(e){ //console.log(this.result); //console.log("当前进度 "+has_loaded/total_size*100+"%"); //}; } }); }); function sleep(numberMillis) { var now = new Date(); var exitTime = now.getTime() + numberMillis; while (true) { now = new Date(); if (now.getTime() > exitTime) { return; } } } </script> </body> </html>