无聊js画了个菱形

function repeat(str, count) {

    return count < 0 ? '' : (new Array(count)).join(str);

}

function diamond(sign, size) {

    var d,

        s = ''

    for (var i = 0; i < size*2; i++) {

        d = Math.abs(size-i-1);

        console.log(d+1, 2*(size-d));

        s += repeat('&nbsp;', d+1) + repeat(sign, 2*(size-d)) + repeat('&nbsp;', d+1) + '<br/>';

    };

    document.write(s);

}

diamond('A', 5);