javascript - Reorganizing an array without sort() and doubles -

i have array named contents:

contents[0]='<button id=' + randomchar0 +' class="btn" onclick="check('+ f + randomchar0 + f +');">' + randomchar0 + '</button>'; contents[1]='<button id=' + randomchar1 +' class="btn" onclick="check('+ f + randomchar1 + f +');">' + randomchar1 + '</button>'; contents[2]='<button id=' + randomchar2 +' class="btn" onclick="check('+ f + randomchar2 + f +');">' + randomchar2 + '</button>'; 

i have tried rearrange code:

function shuffle(array) {   var currentindex = array.length, temporaryvalue, randomindex ;    // while there remain elements shuffle...   while (0 !== currentindex) {      // pick remaining element...     randomindex = math.floor(math.random() * currentindex);     currentindex -= 1;      // , swap current element.     temporaryvalue = array[currentindex];     array[currentindex] = array[randomindex];     array[randomindex] = temporaryvalue;   }    return array; }; 

calling this:

shuffle(contents); 

from how randomize (shuffle) javascript array?

but method gives me doubles quite often.

any idea how make sure buttons change order without doubling , without using sort()?

i want rearrange array make buttons in appear in different order everytime output array. dont want of buttons appear twice accident, means need of buttons output in "random" order.

update: found test of array shufflings, there interesting results.