function NumOnly(e) {
   var KeyCode = (e.keyCode) ? e.keyCode : e.which;
   return ((KeyCode == 8) // backspace
        || (KeyCode == 9) // tab
        || (KeyCode == 37) // left arrow
        || (KeyCode == 39) // right arrow
        || (KeyCode == 46) // delete
        || (KeyCode == 45) // -
		|| (KeyCode == 43) // +
        || ((KeyCode > 47) && (KeyCode < 58)) // 0 - 9
   );
}

function validation() {

if (document.myform.first_name.value.length < 1)
{
alert("Please enter your first name");
document.myform.first_name.focus();
return false;
}

if (document.myform.sur_name.value.length < 1)
{
alert("Please enter your sur name");
document.myform.sur_name.focus();
return false;
}

if (document.myform.address.value.length < 1)
{
alert("Please enter your address");
document.myform.address.focus();
return false;
}

if (document.myform.postcode.value.length < 1)
{
alert("Please enter your post code");
document.myform.postcode.focus();
return false;
}

if (document.myform.telephone.value.length < 5)
{
alert("Please enter your telephone number");
document.myform.telephone.focus();
return false;
}

if (document.myform.comments.value.length < 2)
{
alert("Please enter your comments");
document.myform.comments.focus();
return false;
}

var str=document.myform.main_email.value
var filter=/^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i
if (filter.test(str))
document.myform.comments.focus();
else{
alert("Please input a valid email address!")
document.myform.main_email.focus();
return false;
}

return true;
}