gistfile1.js

function checkRequiredPayments() {
	$('input.payment_sum_field').each(function() { 
		if ($(this).hasClass("required")) {
			var tr = $(this).parents("tr");
			
			var checkbox = $("input[type=checkbox]:first", tr);
			if (!checkbox.attr("checked")) {
				checkbox.attr("checked", true);
			}
			var re = new RegExp("r_([0-9]+)");
			var match = re.exec($(this).attr("class"));
			
			if (match != null) {
				var required_sum = match[1];
				if ($(this).attr("value") * 1 <= required_sum) {
					if ($('input.payment_check:checked').length > 0) {
						$(this).attr("value", required_sum);
						if ($('input.payment_check:checked').length > 1) {
							$("div.required_payment:first").removeClass("hidden");
						}
					}
					else {
						var total = $("#order_total").html() * 1;
						$(this).attr("value", total);
					}
				}
			}
		}
	});
}