jquery.intcheck.js

$.fn.intcheck = function () {
	return this.bind("keyup", function () {
		this.value = this.value.replace(/[^0-9]/g, '');
		if (isNaN(this.value)) {
			while (isNaN(this.value)) {
				var len = this.value.length;
				if (len < 1) break;
				this.value = this.value.substring(0, len - 1);
			}
		}
	});
}