Script injector

index.html

<a href="javascript:(function()%7Bfunction%20callback()%7B(function()%7B%7D)()%7Dvar%20s%3Ddocument.createElement(%22script%22)%3Bs.src%3D%22https%3A%2F%2Fgist.githack.com%2Fbaconscript%2F835d1c57cffd21eca7ba%2Fraw%2Ff9e4453a1b39504030b1590bfa481444706b6475%2Finject.js%22%3Bif(s.addEventListener)%7Bs.addEventListener(%22load%22%2Ccallback%2Cfalse)%7Delse%20if(s.readyState)%7Bs.onreadystatechange%3Dcallback%7Ddocument.body.appendChild(s)%3B%7D)()">Add scripts</a>

inject.js

;(function(){

var libraries = {
  "Lo-Dash": "//cdnjs.cloudflare.com/ajax/libs/lodash.js/3.3.1/lodash.min.js",
  "Underscore":  "//cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.2/underscore-min.js",
  "jQuery":  "//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"
};

function addScript(url, callback)
{
    var head = document.getElementsByTagName('head')[0];
    var script = document.createElement('script');
    script.type = 'text/javascript';
    script.src = url;

    if(callback){
      script.onreadystatechange = callback;
      script.onload = callback;
    }

    head.appendChild(script);
}

addScript('https://raw.githack.com/Nycto/PicoModal/master/src/picoModal.js', function(){
picoModal('')
  .beforeShow(function (modal, event) {
    var content = '', elem = modal.modalElem();
    Object.keys(libraries).forEach(function(libName){
      var src = libraries[libName];
      content += '<a class="btn btn--sm script-btn" data-lib-name="'+libName+'" data-script="'+src+'">'+libName+'</a>';
    });
    elem.innerHTML = content;
    elem.style.textAlign = 'center';
    console.log(elem.childNodes);
    for(var i = 0; i < elem.childNodes.length; i++){
      (function(){
        var btn = elem.childNodes[i];
        btn.onclick = function(){
          btn.innerHTML = '...';
          addScript(btn.dataset.script, function(){
            btn.innerHTML = btn.dataset.libName + ' loaded';
            btn.onclick = null;
            btn.style.opacity = 0.3;
          });
        };
      })();
    }
  })
  .show();
  
}, 100);

// styles from mrmrs's "btns.css"
var css='a.script-btn:hover{text-decoration: none;}'+".pico-content .btn,\n.pico-content .btn:link,\n.pico-content .btn:visited {\n  border-radius: 0.3em;\n  border-style: solid;\n  border-width: 1px;\n  color: #111;\n  display: block;\n  font-family: avenir, helvetica, arial, sans-serif;\n  letter-spacing: 0.15em;\n  margin-bottom: 0.5em;\n  padding: 0.5em 0.75em;\n  text-decoration: none;\n  text-transform: uppercase;\n  -webkit-transition: color 0.4s, background-color 0.4s, border 0.4s;\n  transition: color 0.4s, background-color 0.4s, border 0.4s;\n  cursor: pointer;\n  width: 150px;\n}\n.pico-content .btn:hover,\n.pico-content .btn:focus {\n  color: #7FDBFF;\n  border: 1px solid #7FDBFF;\n  -webkit-transition: background-color 0.3s, color 0.3s, border 0.3s;\n  transition: background-color 0.3s, color 0.3s, border 0.3s;\n}\n.pico-content .btn:active {\n  color: #0074D9;\n  border: 1px solid #0074D9;\n  -webkit-transition: background-color 0.3s, color 0.3s, border 0.3s;\n  transition: background-color 0.3s, color 0.3s, border 0.3s;\n}\n.pico-content .btn--s {\n  font-size: 12px;\n}",
style=document.createElement('style');
if (style.styleSheet)
    style.styleSheet.cssText=css;
else 
    style.appendChild(document.createTextNode(css));
document.getElementsByTagName('head')[0].appendChild(style);

})();

url

javascript:(function()%7Bfunction%20callback()%7B(function()%7B%7D)()%7Dvar%20s%3Ddocument.createElement(%22script%22)%3Bs.src%3D%22https%3A%2F%2Fgist.githack.com%2Fbaconscript%2F835d1c57cffd21eca7ba%2Fraw%2Ff9e4453a1b39504030b1590bfa481444706b6475%2Finject.js%22%3Bif(s.addEventListener)%7Bs.addEventListener(%22load%22%2Ccallback%2Cfalse)%7Delse%20if(s.readyState)%7Bs.onreadystatechange%3Dcallback%7Ddocument.body.appendChild(s)%3B%7D)()