[removed] AppendChild

Answer 1

proper way (rows & cols & the random innerText is set dynamically ...by you) this way is probably not the shortest but by way the fastest to build a table. It’s also a full table with thead and filled with random text:

1. use native JavaScript (not slowing down JQuery)

2. (function(){})() executes the code before body is loading

3. doesn’t have problems with other variables outside the function

4. and pass the document so you have shorter variables

5. there is a way to shorten the function by using clone node... but it’s slower and maybe not supported by all browsers

6. use createDocumentFragment() to create the tr’s. If you have a lot of rows this helps to build the DOM faster.

    (function (d) {
        var rows = 10,
            cols = 3,
            t = d.createElement('table'),
            the = d.createElement('thead'),
            tb = d.createElement('tbody'),
            tr = d.createElement('tr');
        t.style.width = "100%";
        t.style.borderCollapse = 'collapse';
        for (var a = 0; a < cols; a++) {
            var th = d.createElement('th');
            th.innerText = Math.round(Math.random() * 100);
            tr.appendChild(th);
        };
        the.appendChild(tr);
        var f = d.createDocumentFragment();
        for (var a = 0; a < rows; a++) {
            var tr = d.createElement('tr');
            for (var b = 0; b < cols; b++) {
                var td = d.createElement('td');
                td.innerText = Math.round(Math.random() * 100);
                tr.appendChild(td);
            }
            f.appendChild(tr);
        }
        tb.appendChild(f);
        t.appendChild(the);
        t.appendChild(tb);
        window.onload = function () {
            d.body.appendChild(t)
        };
    })(document)