瀏覽器 本地預覽圖片 window.url.createobjecturl

第一種方式

   
   
   
           

    
    
    
            
<script type="text/javascript"> 
    
    
    
            
function setImagePreview() { 
    
    
    
            
var docObj = document.getElementById("ctl00_ContentMain_file_head"); 
    
    
    
            
var fileName = docObj.value; 
    
    
    
            
if (!fileName.match(/.jpg|.gif|.png|.bmp/i)) { 
    
    
    
            
alert('您上傳的圖片格式不正確，請重新選擇！'); 
    
    
    
            
return false; 
    
    
    
            
} 
    
    
    
            
 
    
    
    
            
var imgObjPreview = document.getElementById("preview"); 
    
    
    
            
if (docObj.files && docObj.files[0]) { 
    
    
    
            
//火狐下，直接設img屬性 
    
    
    
            
imgObjPreview.style.display = 'block'; 
    
    
    
            
imgObjPreview.style.width = '63px'; 
    
    
    
            
imgObjPreview.style.height = '63px'; 
    
    
    
            
//imgObjPreview.src = docObj.files[0].getAsDataURL(); 
    
    
    
            
if (window.navigator.userAgent.indexOf("Chrome") >= 1 || window.navigator.userAgent.indexOf("Safari") >= 1) { 
    
    
    
            
imgObjPreview.src = window.webkitURL.createObjectURL(docObj.files[0]); 
    
    
    
            
} 
    
    
    
            
else { 
    
    
    
            
imgObjPreview.src = window.URL.createObjectURL(docObj.files[0]); 
    
    
    
            
} 
    
    
    
            
} else { 
    
    
    
            
//IE下，使用濾鏡 
    
    
    
            
docObj.select(); 
    
    
    
            
docObj.blur(); 
    
    
    
            
var imgSrc = document.selection.createRange().text; 
    
    
    
            
var localImagId = document.getElementById("localImag"); 
    
    
    
            
//必須設置初始大小 
    
    
    
            
localImagId.style.width = "63px"; 
    
    
    
            
localImagId.style.height = "63px"; 
    
    
    
            
//圖片異常的捕捉，防止用戶修改后綴來偽造圖片 
    
    
    
            
try { 
    
    
    
            
localImagId.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)"; 
    
    
    
            
localImagId.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = imgSrc; 
    
    
    
            
} catch (e) { 
    
    
    
            
alert("您上傳的圖片格式不正確，請重新選擇！"); 
    
    
    
            
return false; 
    
    
    
            
} 
    
    
    
            
imgObjPreview.style.display = 'none'; 
    
    
    
            
document.selection.empty(); 
    
    
    
            
} 
    
    
    
            
return true; 
    
    
    
            
} 
    
    
    
            
 
    
    
    
            
</script> 
   
   
   
           

<div id="localImag"><img id="preview" width="-1" height="-1" style="display:none" /></div> 
<asp:FileUpload ID="file_head" runat="server" onchange="javascript:setImagePreview();" /> 

第二種方式

  
  
  
          

   
   
   
           
function setImagePreview(a,b) {
   
   
   
           
 var url ='';
   
   
   
           
 if (navigator.userAgent.indexOf("MSIE")>=1) { // IE
   
   
   
           
 url = document.getElementById(a).value;
   
   
   
           
 } else if(navigator.userAgent.indexOf("Firefox")>0) { // Firefox
   
   
   
           
 url = window.URL.createObjectURL(document.getElementById(a).files.item(0));
   
   
   
           
 } else if(navigator.userAgent.indexOf("Chrome")>0) { // Chrome
   
   
   
           
 url = window.URL.createObjectURL(document.getElementById(a).files.item(0));
   
   
   
           
 }
   
   
   
           
 var imgPre = document.getElementById(b);
   
   
   
           
 imgPre.src = url;
   
   
   
           
}
  
  
  
          

a = fileid

b=imgid