js检测文件类型及大小

function CheckFileType()
        {      
            var objButton=document.getElementById("buttonsubmit");
            var objFileUpload=document.getElementById('Upload');
  
            var objMSG=document.getElementById('msg');
            var FileName=new String(objFileUpload.value);
            var extension=new String (FileName.substring(FileName.lastIndexOf(".")+1,FileName.length));
  
   var image=new Image();  
            image.dynsrc=objFileUpload.value;
   var FileSize=Math.round(image.fileSize/1024*100)/100;
   if(FileSize>100)
   {
    objButton.disabled=true;
                objMSG.innerHTML="<div style='border:#CCCCCC dotted 1px; background-color:#FFFFCC; padding:5px; margin:10px auto; color:#FF0000;'>File too large.</div>";
    return;
   }
  
            if(extension.toLowerCase()=="xls"||extension.toLowerCase()=="csv")
            {
                 objButton.disabled=false;
                 objMSG.innerHTML="";
            }
            else
            {
                  objButton.disabled=true;
                  objMSG.innerHTML="<div style='border:#CCCCCC dotted 1px; background-color:#FFFFCC; padding:5px; margin:10px auto; color:#FF0000;'>FileType error.</div>";
             }
        }  

______________________________________________________________
function CheckFileType()
        {      
            var objButton=document.getElementById("buttonsubmit");
            var objFileUpload=document.getElementById('Upload');
   var FileSize=Math.round(getFileSize(objFileUpload.value)/1024*100)/100;//取得图片文件的大小
            var objMSG=document.getElementById('msg');
            var FileName=new String(objFileUpload.value);
            var extension=new String (FileName.substring(FileName.lastIndexOf(".")+1,FileName.length));
  
   if(FileSize>100)
   {
    objButton.disabled=true;
                objMSG.innerHTML="<div style='border:#CCCCCC dotted 1px; background-color:#FFFFCC; padding:5px; margin:10px auto; color:#FF0000;'>File too large.</div>";
    return;
   }
  
            if(extension.toLowerCase()=="xls"||extension.toLowerCase()=="csv")
            {
                 objButton.disabled=false;
                 objMSG.innerHTML="";
            }
            else
            {
                  objButton.disabled=true;
                  objMSG.innerHTML="<div style='border:#CCCCCC dotted 1px; background-color:#FFFFCC; padding:5px; margin:10px auto; color:#FF0000;'>FileType error.</div>";
             }
        }
  
  function getFileSize(filePath)  
         {  
            var image=new Image();  
            image.dynsrc=filePath;  
            
            return image.fileSize;     //不是图片文件也能检测其大小
          
         }