Tampermonkey: Inject jQuery and Do Something With It

jQueryception.js

// Gets called when jQuery is all loaded and ready to go.
// Use jq instead of $ here. For instance,
//      jq("div") or jq.get("targeturl");
function runWith(jq) {
    // Do cool stuff here
}

// Get jquery, copied this from here http://blog.reybango.com/2010/09/02/how-to-easily-inject-jquery-into-any-web-page/
// with some minor modifications to do a callback whenever jQuery is either detected as having already
// been loaded or is done loading.
(function() {
    var el=document.createElement('div'),
        b=document.getElementsByTagName('body')[0];
    otherlib=false,
        msg='';
    el.style.position='fixed';
    el.style.height='32px';
    el.style.width='220px';
    el.style.marginLeft='-110px';
    el.style.top='0';
    el.style.left='50%';
    el.style.padding='5px 10px';
    el.style.zIndex = 1001;
    el.style.fontSize='12px';
    el.style.color='#222';
    el.style.backgroundColor='#f99';
    if(typeof jQuery!='undefined') {
        msg='This page already using jQuery v'+jQuery.fn.jquery;
        runWith(jq);
        //return showMsg();
    } else if (typeof $=='function') {
        otherlib=true;
    }
    // more or less stolen form jquery core and adapted by paul irish
    function getScript(url,success){
        var script=document.createElement('script');
        script.src=url;
        var head=document.getElementsByTagName('head')[0],
            done=false;
        // Attach handlers for all browsers
        script.onload=script.onreadystatechange = function(){
            if ( !done && (!this.readyState
                           || this.readyState == 'loaded'
                           || this.readyState == 'complete') ) {
                done=true;
                success();
                script.onload = script.onreadystatechange = null;
                head.removeChild(script);
            }
        };
        head.appendChild(script);
    }
    getScript('http://code.jquery.com/jquery-latest.min.js',function() {
        if (typeof jQuery=='undefined') {
            msg='Sorry, but jQuery wasn\'t able to load';
        } else {
            runWith(jQuery);
            msg='This page is now jQuerified with v' + jQuery.fn.jquery;
            if (otherlib) {msg+=' and noConflict(). Use $jq(), not $().';}
        }
        return showMsg();
    });
    function showMsg() {
        // Remove this return statement if you're having trouble getting jquery up and running
        return;
        el.innerHTML=msg;
        b.appendChild(el);
        bodyOfWork();
        window.setTimeout(function() {
            if (typeof jQuery=='undefined') {
                b.removeChild(el);
            } else {
                jQuery(el).fadeOut('slow',function() {
                    jQuery(this).remove();
                });
                if (otherlib) {
                    $jq=jQuery.noConflict();
                }
            }
        } ,2500);
    }
})();