function include_js(file) {
    var _doc = document.getElementsByTagName('head')[0];
    var js = document.createElement('script');
    js.setAttribute('type', 'text/javascript');
    js.setAttribute('src', file);
    _doc.appendChild(js);

    if (!/*@[email protected]*/0) { //if not IE
        //Firefox2、Firefox3、Safari3.1+、Opera9.6+ support js.onload
        js.onload = function () {
            alert('Firefox2、Firefox3、Safari3.1+、Opera9.6+ support js.onload');
        }
    } else {
        //IE6、IE7 support js.onreadystatechange
        js.onreadystatechange = function () {
            if (js.readyState == 'loaded' || js.readyState == 'complete') {
                alert('IE6、IE7 support js.onreadystatechange');
            }
        }
    }

    return false;
}

include_js('http://www.planabc.net/wp-includes/js/jquery/jquery.js');

</script>

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另一種寫法：

function addScript(jsfile,callback){
    var head= document.getElementsByTagName('head')[0];
 
var script= document.createElement('script');
script.type= 'text/javascript';
script.src= jsfile;
head.appendChild(script);script.onload = script.onreadystatechange = function() {
        if (!this.readyState || this.readyState === "loaded" ||    this.readyState === "complete" ) {
            script.onload 
 
= script.onreadystatechange = null;            if(callback&&typeof(callback)== 'function'){
callback();//window[callback]();如果傳遞字串過來  呼叫window['函式名']() 呼叫方法}
}
    };
}