图片上传预览

function setImagePreview() {
         var docObj = document.getElementById("doc");
         var fileName = docObj.value;
         var imgObjPreview = document.getElementById("preview");
         if (docObj.files && docObj.files[0]) {	//火狐下，直接设img属性
             imgObjPreview.style.display = 'block';
             imgObjPreview.style.width = '120px';
             imgObjPreview.style.height = '150px';
             imgObjPreview.src = docObj.files[0].getAsDataURL();
         }
         else {	//IE下，使用滤镜
             docObj.select();
             var imgSrc = document.selection.createRange().text;
             var localImagId = document.getElementById("localImag");
             //必须设置初始大小
             localImagId.style.width = "120px";
             localImagId.style.height = "150px";
             //图片异常的捕捉，防止用户修改后缀来伪造图片
             try {
                 localImagId.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)";
                 localImagId.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = imgSrc;
             }
             catch (e) {
                 alert("您上传的图片格式不正确，请重新选择!");
                 return false;
             }
             imgObjPreview.style.display = 'none';
             document.selection.empty();
         }
         return true;
     }