function isValidEmail(str){
   return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
}
function chkSubmit(){
	if(document.forms[0].name.value=="")
	{
		alert("Please enter your name.");
		return;
	}
	if(document.forms[0].address.value=="")
	{
		alert("Please enter your address.");
		return;
	}
	if(document.forms[0].phone.value=="")
	{
		alert("Please enter your phone number.");
		return;
	}
	if(document.forms[0].mail.value=="")
	{
		alert("Please enter your e-mail address.");
		return;
	}
	if(isValidEmail(document.forms[0].mail.value)==false)
	{
		alert("Invalid e-mail address.");
		return;
	}
	if(document.forms[0].comment.value=="")
	{
		alert("Please enter your query.");
		return;
	}
	document.forms[0].submit();
}