JavaScript代码改进

Question

我不是一个巨大的JavaScript性能大师.简单地想知道,我可以将以下代码更紧凑吗？不像打包或压缩它,而是按照它的编写方式.

(function() {
    var jq = document.createElement('script');
    var an = document.createElement('script');
    var cm = document.createElement('script');
    var ga = document.createElement('script');
    var domain = 'http://example.com/';

    jq.src = domain + 'jquery.1.3.2.js';
    an.src = domain + 'jquery.alphanumeric.js';
    cm.src = domain + 'common.js';
    ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
    ga.setAttribute('async', 'true');

    document.documentElement.firstChild.appendChild(jq);
    document.documentElement.firstChild.appendChild(cm);
    document.documentElement.firstChild.appendChild(an);
    document.documentElement.firstChild.appendChild(ga);
})();

干杯啦!

Answer 1

写作方式的紧凑性和性能是无关的.但要以更紧凑,可重复使用的方式编写它:

function appendScript(url, async) {
    var el = document.createElement('script'),
        root = document.documentElement;
    el.async = async;
    el.src = url;
    // avoid an IE6 bug by using insertBefore (http://bugs.jquery.com/ticket/2709)
    root.insertBefore(el, root.firstChild);
}


appendScript('http://example.com/js/jquery.1.3.2.js', false);
appendScript('http://example.com/js/jquery.alphanumeric.js', false);
appendScript('http://example.com/js/common.js', false);
appendScript(('https:' == document.location.protocol ? '//ssl' : '//www') + '.google-analytics.com/ga.js'), true);