function IsNumeric(input){
	var RE = /^-{0,1}\d*\.{0,1}\d+$/;
	return (RE.test(input));
}


jQuery(function() {
	jQuery('form#pricecheck').submit(function() {
		if (jQuery('#priceyp').val() != '') {
			if (IsNumeric(jQuery('#priceyp').val())) {
				jQuery('#yes').val('YES!');
			} else {
				jQuery('#yes').val('You must enter a valid price - no symbols etc');
			}
		} else {
			jQuery('#yes').val('You must enter a price');
		}

	}); 
});