Friday, December 12, 2014

How to Validate Image Extension in JavaScript ?



<!DOCTYPE>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Image extension validation in javascript</title>
<script type="text/javascript">
function checkExtension(filename)
{
 var n= filename.lastIndexOf(".");
 if(n != -1) //which means filename has . 
 {
  var st= filename.substring(n);
  if(st==".jpg" || st==".jpeg" || st==".png" || st==".gif")
  { //correct extension
   return true;
  }
   else
   { 
    //incorrect extension
   return false;
   }
 }
 else
 {
  //filname don't contains .
  return false;
 }
}
function check()
{
 var fname=document.frm.filename.value;
 if(fname=='')
 {
 alert('select image')
 return false;
 }
 else if(checkExtension(fname))
 return true;
 else 
 {
  alert('Invalid image file. Should be a image !!!')
 return false;
 }
}
</script>
</head>

<body>
<h1 align="center">Image extension validation in javascript.</h1>
<div align="center">
<form name="frm" onsubmit="return check()" method="post" action="go.html">
Select File: 
<input type="file" name="filename" id="filename" />
<br/> <br/>
<input type="submit" />
</form>
</div>
</body>
</html> 

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