function isDigit (c) {
	return ((c >= "0") && (c <= "9")) ;
}



function isInteger (s) {
	var i ;
	var c ;
	for (i = 0; i < s.length; i++) {
		c = s.charAt(i) ;
		if (!isDigit(c)) return false ;
	}
	return true
}


function checkform( thisform ) {
	if (thisform.ZipQuery.value == null || thisform.ZipQuery.value == "" ) {
		alert ("You must enter a zip code to continue.") ;
		thisform.ZipQuery.focus() ;
		thisform.ZipQuery.select() ;
		return false ;
	}
	if (!isInteger(thisform.ZipQuery.value)) {
		alert ("You must enter a numeric zip code to continue.") ;
		thisform.ZipQuery.focus() ;
		thisform.ZipQuery.select() ;
		return false ;
	}
	if (thisform.ZipQuery.value.length != 5) {
		alert ("You must enter a 5 digit zip code to continue.") ;
		thisform.ZipQuery.focus() ;
		thisform.ZipQuery.select() ;
		return false ;
	}
	return true
}