javascript发送验证码

一个发送验证码的javascript代码

var T = 0;
var handle = null;
var event = null;
$(function(){
    $('#sendCode').click(function(e){
        if(T == 0) {
            var mobile = $('#name').val();
            if (!/^(13[0-9]|14[0-9]|15[0-9]|18[0-9])\d{8}$/i.test(mobile)) {
                alert('请先填写正确的手机号码');
                return false;
            }

            $.post('/auth/sendcode', {mobile: mobile, _token: 'HyOSLkoOpvawVZZi6LUYfNIryJZvc2mXnOJYrrDJ'}, function (res) {
                if (res.state == 'success') {
                    T = 59;
                    countDown();
                } else {
                    alert(res.message);
                }
            }, 'json');

        } else {
            e.stopPropagation();
        }
    });
});
function countDown()
{
    $('#sendCode').text(T+'秒后可重新获取').css({'background-color':'#f8f8f8', 'color' : '#cccccc'});
    T = T - 1;
    handle = setTimeout('countDown()', 1000);
    if (T < 0) {
        clearTimeout(handle);
        $('#sendCode').text('重新获取').css({'background-color':'#eeeeee', 'color' : '#555555'});
        T = 0;
    }
}