greasemonkey_choose_quiz_questions

// ==UserScript==
// @name        choose_quiz_questions
// @namespace   com.YOUR_NAMESPACE.quiz
// @include     http://YOUR_MOODLE_SITE/mod/quiz/*
// @version     1
// @grant       none
// ==/UserScript==

var numberOfQuizQuestions = 25;
var numberOfBankQuestions = 200;

window.addButton = function () {
	var newDiv = document.createElement('div');
	newDiv.setAttribute('id','buttonDiv');
		
	var inputButton = document.createElement('input');
	inputButton.type = 'button';
	inputButton.value = 'Choose 25 random questions';
	inputButton.addEventListener('click', go_go_checkboxes, false);
	document.getElementsByTagName("body")[0].appendChild(newDiv);
	document.getElementById("buttonDiv").appendChild(inputButton); 
}
addButton();

var myButtonDiv = document.getElementById("buttonDiv");
myButtonDiv.style.position = "fixed";
myButtonDiv.style.left = "0px";
myButtonDiv.style.bottom = "0px";
myButtonDiv.style.backgroundColor = "black";



var inputs=document.getElementsByTagName('input');
var checkboxes=[];
for (var i=0; i< inputs.length; i++){
	if (inputs[i].type=="checkbox" && inputs[i].title=="Select"){
		checkboxes.push(inputs[i]);
	}
}


// console.log("checkboxes: "+checkboxes.length);

function go_go_checkboxes() {
	randomArray =[];
	while (randomArray.length < numberOfQuizQuestions) {
		var randomNumber=RandomNumber(0 , numberOfBankQuestions - 1);
		var found=false;
		for (var i=0; i<randomArray.length; i++){
			if(randomArray[i]==randomNumber){
				found=true;
				break;
			}
		} 
	
		if(!found){
			randomArray.push(randomNumber);	
		}
	}

	for (var i=0; i<randomArray.length; i++){
		console.log(i + ": " +randomArray[i]);
	}
	
//	console.log("checkboxes: "+inputs.length);
//	console.log("checkboxes: "+checkboxes.length);

	for (var i=0; i < checkboxes.length; i++){
			checkboxes[i].checked=false;
	}
	
	for (var i=0; i< randomArray.length; i++) {
		checkboxes[randomArray[i]].checked=true;
	}

}

function RandomNumber(min,max) {
if(max<min) {
   var i=max;
   max=min;
   min=i;
   }
return Math.round(Math.random()*(max-min)+min);
}