js选中指定dom文本

    function selectAll(id) {
        var h = document, i = h.getElementById(id), d, g;
        if (h.body.createTextRange) {
            d = document.body.createTextRange();
            d.moveToElementText(i);
            d.select()
        } else {
            if (window.getSelection) {
                g = window.getSelection();
                d = document.createRange();
                d.selectNodeContents(i);
                g.removeAllRanges();
                g.addRange(d)
            }
        }
    }