function validate() 
{
   var nm = document.getElementById("txtName").value;
   var comment = document.getElementById("txtComments").value;
   if (nm == "")
   {
        alert('Name must required.')
        return false;
   }
      //Email Validation
    var emailID=document.getElementById("txtEmail");
	
	if ((emailID.value==null)||(emailID.value=="")){
		alert("Please Enter your Email ID")
		emailID.focus()
		return false
	}
	if (echeck(emailID.value)==false){
		emailID.value=""
		emailID.focus()
		return false
	}
    //-----------------------
   if (comment == "")
   {
        document.getElementById("lblmessage").style.visibility = "visible";
        alert('Comments must required.');
        return false;
   }
      //Validation of File Uploading
       var OK = new Array ('jpg', 'gif', 'jpeg', 'png');
       var filename = document.getElementById("txtPicture").value;
       var ext = getExt(filename);
       var fileOK = 0;
     
       for (i = 0; i < OK.length; i++) 
       {
         if (OK[i] == ext) 
         {
          fileOK = 1; // one of the file extensions found
          return true;
         } 
         else
         {
            if (filename != "") 
            {
                alert('Invalid file extension.');
                return false;
            }
         }
       }
}
function getExt(filename) {
   var dot_pos = filename.lastIndexOf(".");
   if(dot_pos == -1)
      return "";

   return filename.substr(dot_pos+1).toLowerCase();
}
//the function is part of email validation
function echeck(str) {

		var at="@"
		var dot="."
		var lat=str.indexOf(at)
		var lstr=str.length
		var ldot=str.indexOf(dot)
		if (str.indexOf(at)==-1){
		   alert("Invalid E-mail ID")
		   return false
		}

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		   alert("Invalid E-mail ID")
		   return false
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		    alert("Invalid E-mail ID")
		    return false
		}

		 if (str.indexOf(at,(lat+1))!=-1){
		    alert("Invalid E-mail ID")
		    return false
		 }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    alert("Invalid E-mail ID")
		    return false
		 }

		 if (str.indexOf(dot,(lat+2))==-1){
		    alert("Invalid E-mail ID")
		    return false
		 }
		
		 if (str.indexOf(" ")!=-1){
		    alert("Invalid E-mail ID")
		    return false
		 }

 		 return true}