参考了网上一些人代码写了一个上传图片及时预览的功能
<img alt="" /> <input type="file" /> function DisplayImage(fileTag,imgTagId){ var allowExtention=".jpg.png.gif"; var extentionArr=fileTag.value.split('.'); var extention = extentionArr[extentionArr.length-1]; if(!(allowExtention.indexOf(extention)>-1)){ alert("Please upload image!"); }else{ //for adveced broswer(the newest ie,chrome,ff) if(typeof(FileReader)!=="undefined"){ var reader = new FileReader(); reader.readAsDataURL(fileTag.files[0]); reader.onload = function(e){ document.getElementById(imgTagId).setAttribute("src", e.target.result); } }else{ //for(ie6) document.getElementById(imgTagId).setAttribute("src",fileTag.value); } } }