求取星期几！！！求大神帮助

Question

选取的年份 来求星期几


这张图片有说明 我吧我的js贴出来 你们帮我看看 那不对 谢谢

 function tuaisuan(){
    var shijian = $("#EntTime32").val();
    var arr = shijian.split('-');

    var nian = parseFloat(arr[0]);
    var yue = parseFloat(arr[1]);
    var ri = parseFloat(arr[2]);
    var shiji =  parseFloat(arr[0].substring(0,2));
    var nian1 =  parseFloat(arr[0].substring(2));

    //求星期
    if(yue<3){
        var yue1=yue+12
        /*var xingqi = parseFloat(nian1+[nian1/4]+[shiji/4]-2*shiji+[26*(yue1+1)/10]+ri-1);
        alert(xingqi);
        不知道为什么结果不对 我只好给他分段计算了
        */
            var s1 = nian1/4
            var s2 = shiji/4
            var s3 = 2*shiji
            var s4 = 26*(yue1+1)/10
            var s5 = parseInt(nian1+s1+s2-s3+s4+ri-1)
            alert(s4);alert(s5);

        }else{
            //var xingqi = parseInt(nian1+[nian1/4]+[shiji/4]-2*shiji+[26*(yue+1)/10]+ri-1);alert(xingqi); 不知道为什么结果不对 我只好给他分段计算了
            var s1 = nian1/4
            var s2 = shiji/4
            var s3 = 2*shiji
            var s4 = 26*(yue+1)/10
            var s5 = parseInt(nian1+s1+s2-s3+s4+ri-1)
            /*alert(s1);alert(s2);alert(s3);*/alert(s4);alert(s5);

            }

Answer 1

function tuaisuan(){
var shijian = "2016-07-01";
var arr = shijian.split('-');
var cen,year,month,day;
if (parseInt(arr[1]) < 3) {
arr[0] = (parseInt(arr[0]) - 1).toString();
arr[1] = (parseInt(arr[1]) + 12).toString();
}
cen = parseInt(arr[0].substr(0,2));
year = parseInt(arr[0].substr(2,2));
month = parseInt(arr[1]);
day = parseInt(arr[2]);
var week = year + Math.floor(year / 4) + Math.floor(cen / 4) - 2 * cen + Math.floor(26 * (month + 1) / 10) + day - 1;
alert(week%7);
}