function emptyvalidation(entered)
{
with (entered)
{
if (value==null || value=="")
{alert("Please ensure all boxes are correctly completed"); return false;}
else {return true;}
}
} 

function postcodevalidation(entered)
{
with(entered)
{
var stripped = value.replace(/[^\dA-Z]+/g, "");
var postCodeFilter = /^[A-Z]{2}[\d]{2,3}[A-Z]{2}$/;
if (!(postCodeFilter.test(stripped))) 
{
	alert ("Please enter a valid post code");
	return false;
}
else
{
	return true;
}
}
}

function formvalidation(thisform)
{
with (thisform)
{
if (emptyvalidation(name)==false) {name.focus(); return false;};
if (emptyvalidation(address)==false) {address.focus(); return false;};
if (postcodevalidation(post_code)==false) {post_code.focus(); return false;};
}
}