<span id="preview" style="display: none;" > </span>
      <br>
      
        图&nbsp;&nbsp;&nbsp;&nbsp;片：
       
       <input type="file" name="picFile" style="width:80% ;"
         onchange="javascript:previewImage(this,'preview',120);" />
      <br>

 function previewImage(picFile,picViewSpanName,picWidth)
{
  var previewSpan=document.getElementById(picViewSpanName);
if(picFile.value=='')
{
 return ;
}
else
{
 previewSpan.style.display="block";
}
if(picWidth=='')
{
  picWidth=120;
}
var fileext=picFile.value.substring(picFile.value.lastIndexOf("."),picFile.value.length)
fileext=fileext.toLowerCase()   
if ((fileext!='.jpg')&&(fileext!='.jpeg')&&(fileext!='.png')&&(fileext!='.bmp'))
{

picFile.focus();
}
else
{
//alert(''+document.form1.picFile.value
    document.getElementById(picViewSpanName).innerHTML="<table border='1'><tr><td><img src='"+picFile.value+"' width='"+picWidth+"' style='border:6px double #ccc'><br>ÉÏ´«Í¼Æ¬Ô¤ÀÀ</td></tr></table>"
} 
}