Format JavaScript date as yyyy-mm-dd

Question

I have a date with the format Sun May 11,2014. How can I convert it to 2014-05-11 using JavaScript?

Answer 1

format = function date2str(x, y) {
    var z = {
        M: x.getMonth() + 1,
        d: x.getDate(),
        h: x.getHours(),
        m: x.getMinutes(),
        s: x.getSeconds()
    };
    y = y.replace(/(M+|d+|h+|m+|s+)/g, function(v) {
        return ((v.length > 1 ? "0" : "") + eval('z.' + v.slice(-1))).slice(-2)
    });

    return y.replace(/(y+)/g, function(v) {
        return x.getFullYear().toString().slice(-v.length)
    });
}

Result:

format(new Date('Sun May 11,2014'), 'yyyy-MM-dd')
"2014-05-11