js判斷圖片大小方法

//判斷照片大小

function getPhotoSize(obj){

     var fileSize = 0;

     var isIE = /msie/i.test(navigator.userAgent) && !window.opera;           

     if (isIE && !obj.files) {         

          var filePath = obj.value;           

          var fileSystem = new ActiveXObject("Scripting.FileSystemObject");  

          var file = fileSystem.GetFile (filePath);              

          fileSize = file.Size;        

     }else { 

          fileSize = obj.files[0].size;    

     }

     fileSize=Math.ceil(fileSize/1024); //單位為KB

     

     return fileSize;

}

<input name="file" size="30" type="file" onchange="getFileSize(this.value)" />