Notes

var pickedItem= [];
var teams=[];

teams[0]='England';
teams[1]='Russia';
teams[2]='Spain';
teams[3]='Germany';
teams[4]='Argentina';
teams[5]='Brazil';
teams[6]='France';
teams[7]='Cuba';

function createLi(text1 , text2){
var body = document.getElementsByTagName('body');
var ul = document.createElement('ul');

body[0].appendChild(ul);

var li = document.createElement('li');

var text = document.createTextNode(text1+ ' vs '+text2);
li.appendChild(text);
ul.appendChild(li);
}
function removieUl() {
var oldUl = document.getElementsByTagName('ul');
if(oldUl.length>0){
oldUl[0].parentNode.removeChild(oldUl[0]); //stays in first array only
}
// body...
}
function checkArray(array, value){
var res= false;
for (var j=0; j< array.length; j++) {
if(array[j]== value) res=true;
}

return res;
}
function newRandom(array,value){
var pickAgain =true;
while(pickAgain==true){
var r= Math.floor(Math.random()*value);
var picked= checkArray(pickedItem,r);

if(picked==false){
pickAgain =false;
}

return r;

}


function buttonClicked(){

//unique random r1
for(var i =0; i< 4; i++){
var r1 = newRandom(pickedItem,4);
var r2= newRandom(pickedItem,4);
}
pickedItem.push(r1);
pickedItem.push(r2);
createLi(pickedItem,r1,r2);


}





function myLoad(){
var button= document.getElementsByTagName('button');
button[0]= document.addEventListener('click', buttonClicked);
}

document.addEventListener('DOMContentLoaded', myLoad);