这是js代码：
<script type="text/javascript"> function upPic(target,e){ /* 检测上传文件的类型 */ var src=e.target||window.event.srcElement; //获取事件源，兼容chrome/IE var filename=src.value; var imgName=filename.substring(filename.lastIndexOf( '\\')+1); var ext,idx; if(imgName == ''){ alert("请选择需要上传的图片！"); return; }else{ idx = imgName.lastIndexOf("."); if(idx != -1){ ext = imgName.substr(idx+1).toUpperCase(); ext = ext.toLowerCase(); if(ext != 'jpg' && ext != 'png' && ext != 'jpeg' && ext != 'gif'){ alert("只能上传.jpg .png .jpeg .gif类型的文件!"); return; } }else{ alert("只能上传.jpg .png .jpeg .gif类型的文件!"); target.value = ""; return; } } var isIE = /msie/i.test(navigator.userAgent) && !window.opera; var fileSize = 0; if(isIE && !target.files){ var filePath = target.value; var fileSystem = new ActiveXObject("Scription.FileSystemObject"); var file = fileSystem.GetFile(filePath); fileSize = file.Size; }else{ fileSize = target.files[0].size; } //验证大小 if(fileSize>1024*1024){ alert("图片过大不能上传"); return } //验证宽高 checkImgPX(target, 240, 300,target.files[0]); }; //检查图片的宽高是否符合要求 function checkImgPX(ths, width, height,fil) { var objUrl = getObjectURL(fil) ; var img = null; img = document.createElement("img"); document.body.insertAdjacentElement("beforeEnd", img); // firefox不行 img.style.visibility = "hidden"; img.src = objUrl; var imgwidth=0; var imgheight=0; if(img.complete){/*判断是否图片在本页面完成加载*/ imgwidth = img.offsetWidth; imgheight = img.offsetHeight; }else{ img.onload = function(){/*待图片加载后获取宽和高*/ imgwidth = img.offsetWidth; imgheight = img.offsetHeight; alert(imgwidth+","+imgheight); if(imgwidth!=width || imgheight!=height) { alert("必须是240像素*300像素的图片"); ths.value = ""; return }else{ console.log("objUrl = "+objUrl) ; if (objUrl) {/*图片预览展示*/ var element = document.getElementById('xuantupian'); alert(objUrl); element.src = 'objUrl'; } } }; } } //建立一個可存取到該file的url function getObjectURL(file) { var url = null ; if (window.createObjectURL!=undefined) { // basic url = window.createObjectURL(file) ; } else if (window.URL!=undefined) { // mozilla(firefox) url = window.URL.createObjectURL(file) ; } else if (window.webkitURL!=undefined) { // webkit or chrome url = window.webkitURL.createObjectURL(file) ; } return url ; }//end </script>
