function chk(that) { 
 
  if(that.contact_name.value=="" || that.contact_name.value=="NULL")
  {
	alert("Please enter Contact Name");
	that.contact_name.focus();
	return false;
  }
  if(that.company_name.value=="" || that.company_name.value=="NULL")
  {
	alert("Please enter Company Name");
	that.company_name.focus();
	return false;
  }
  if(that.sender_email.value == "")
  {
	alert("please enter an e-mail address.");
	that.sender_email.focus();
	return false;
	}
	tmp=document.requestform.sender_email.value;
	if(tmp != null && tmp != ""){
		var emailRegEx = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
		str = tmp;
		if(!str.match(emailRegEx)){
			alert('Please enter valid email address.');
			document.requestform.sender_email.focus();
			return false;
		}	
	}
  if(that.sender_phone_no.value=="" || that.sender_phone_no.value=="NULL")
  {
	alert("Please enter Phone No");
	that.sender_phone_no.focus();
	return false;
  }
 }