function checkform() 
{
if(!isNaN(document.contact.name.value))
{
alert("Please Enter the Name Field");
document.contact.name.focus();
return false;
}
<!--telephone validation-->
if(document.contact.email.value == "")
{
alert("Please Enter the Email Field");
document.contact.email.focus();
return false;
}
if(!isEmail(document.contact.email.value))
{
alert("Please Check the Email Format");
document.contact.email.focus();
return false;
}
else 
{
	return true;
}
}