Browser Compatibility Issues (works in Chrome only)

<script>
var correctAnswers =0;
var randomItem; 
var selected;
var selectedQuestion;
var testing = "this is a test of testing";
var questionCheckResult = false;
var displayedQuestion = '';
var divID =0;
var questionBox = 'questionBox0';
var originalArrayLength;
var answersArray =[];
var questionArray=[[
    ['What do you do at a red light?'],
        ['Drive fast so you dont get the red light.',0],
        ['Stop',1],
        ['Run over the guy in the crosswalk', 0],
        ['Bump Taylor Swift till you feel better',0]],
    [['Can you pass in a schoul zone?'],
        ['Yes.',0],
        ['No',1],
        ['Run them kids over!', 0],
        ['Remember back to the good ole days.',0]
    ],
    [['How fast do you drive on the freeway?'],
        ['There\'s a limit?',0],
        ['65 Miles Per Hour',1],
        ['42', 0],
        ['Faster than the guy behind you.',0]
    ]
]

var callQuestion = function(number){
    displayedQuestion = '';
    displayedQuestion +='<div id="questionBox'+divID+'" class="questionBox">';
    displayedQuestion += '<center>'+questionArray.length+' Questions Left</center>';
    if (questionCheckResult){
        displayedQuestion +='<div class="questionHeader">'+questionCheckResult+'</div>';
    }
    displayedQuestion +='<div class="questionHeader">'+questionArray[number][0]+'</div>';
    for(var i2 =1;i2<=4;i2+=1){
        selectedQuestion = i2;
        answersArray.push('<button type="button" class="btn btn-info" value="testing" id="answer" onclick="questionCheck(randomItem, '+selectedQuestion+')">'+questionArray[number][i2][0]+'</button><br>');
    }
    shuffle(answersArray);
    for(var i2 =0;i2<=3;i2+=1){
        displayedQuestion += answersArray[i2];
    }
    answersArray = [];
    displayedQuestion +='</div>';
    document.write(displayedQuestion);
}
function shuffle(array) {
  var currentIndex = array.length, temporaryValue, randomIndex ;
  while (0 !== currentIndex) {
    randomIndex = Math.floor(Math.random() * currentIndex);
    currentIndex -= 1;
    temporaryValue = array[currentIndex];
    array[currentIndex] = array[randomIndex];
    array[randomIndex] = temporaryValue;
  }

  return array;
}
var randomQuestion = function(){
    var randomArrayItem = [Math.floor(Math.random() * questionArray.length)];
    return randomArrayItem;
}
var questionCheck = function(array, clickedAnswer){
    questionBox = "questionBox'+divID+'";
    if(divID > 0){
        removeQuestionBox();
    }
    divID += 1;
    callHeaders();
    console.log(array, clickedAnswer);
    if (questionArray[array][clickedAnswer][1] == 1){
        questionArray.splice([array], 1 );
        questionCheckResult = '<font color="green">Your Answer Was Correct</font>';
    }else{
        questionCheckResult = '<font color="red">Your Answer Was Incorrect</font>';
    }
    if (questionArray.length > 0){
        randomItem = randomQuestion();
        callQuestion(randomItem);
    }else{
        document.write('<center>There are no questions left!</center>');
    }
}
var callHeaders = function(){
    document.write('<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css" rel="stylesheet"><style>.questionBox{margin:10px; background: #b6fcd5; border: solid #8dcd91 2px; padding:10px; max-width:340px;min-width:340px; border-radius: 5px; margin-right:auto;margin-left:auto;}button{margin:10px; max-width:300px;min-width:300px;}.questionHeader{text-align: center;font-weight: bold; padding-bottom: 5px;}</style>');
}
var removeQuestionBox = function(){
 var elem = document.getElementById('questionBox'+divID);
 elem.parentNode.removeChild(elem);
}
originalArrayLength = questionArray.length;
callHeaders();
randomItem = randomQuestion();
document.write(questionArray.length);
document.write(randomItem);
callQuestion(randomItem);

</script>