Change background on div with Javascript - php

Question

This is my a management exam that I'm trying to make a modification. The exam shows questions one by one hiding the other
When I press on one of the answers if the answer is correct, right before going to the next question the background
of the pressed question goes green if it was the correct answer, red if it was the wrong answer.
What I want: When the user presses the wrong answer I want the system not only to show a red background for the pressed button but
also make the background of the correct answer green. Showing this way to the user what was the correct answer. If I missed code please let me know.
PHP
$orderbyrand = "SELECT * FROM management
ORDER BY rand(), `answer` ASC LIMIT 2";
$rend_result=mysql_query($orderbyrand);
$k=1;
while($row_rand=mysql_fetch_array($rend_result)){
$answerarry[$k]= $row_rand['answer'];
$k++;}
$answerarry['0'] = $answerarry_shuffle['0'];
$answerarry['1'];
$answerarry['2'];
shuffle($answerarry);
if($answerarry_shuffle['0']==$answerarry[0])
{ $correcr_answer[0]=1; } else { $correcr_answer[0]=0; }
if($answerarry_shuffle['0']==$answerarry[1])
{ $correcr_answer[1]=1; } else { $correcr_answer[1]=0; }
if($answerarry_shuffle['0']==$answerarry[2])
{ $correcr_answer[2]=1; } else { $correcr_answer[2]=0; }
Javascript
function change_question(quest_num,optionvalue,ans_div_num){
var hidediv = 'question_'+optionvalue;
var add_optionvalue = (Number(optionvalue)+Number(1));
var showdiv = 'question_'+add_optionvalue;
var noofques = document.getElementById('noofques').value;
var totalno = (Number(noofques)+Number(1));
var totalcount = document.getElementById('noofques').value=totalno;
if(quest_num==1){
var correct_answer = document.getElementById('optvalue').value;
var optinoresult_add = (Number(correct_answer)+Number(1));
var addoptvalue = document.getElementById('optvalue').value=optinoresult_add;
document.getElementById('answerdiv_'+ans_div_num+'_'+optionvalue).style.background='#bbd387';
} else {
var correct_answer = document.getElementById('optvalue').value;
var optinoresult_add = (Number(correct_answer)+Number(0));
var addoptvalue = document.getElementById('optvalue').value=optinoresult_add;
if(ans_div_num!=0){
document.getElementById('answerdiv_'+ans_div_num+'_'+optionvalue).style.background='#dd5f5b'; }
}
}
HTML
<div class="row-fluid answer">
<div id="answerdiv_1_<?php echo $i; ?>" onClick="return change_question('<?php echo $correcr_answer[0]; ?>','<?php echo $i; ?>','1');" class="span12 show_cursor"><p><?php echo substr($answerarry[0],0,300);?></p></div>
</div>
<div class="row-fluid answer">
<div id="answerdiv_2_<?php echo $i; ?>" onClick="return change_question('<?php echo $correcr_answer[1]; ?>','<?php echo $i; ?>','2');" class="span12 show_cursor"><p><?php echo substr($answerarry[1],0,300);?></p> </div>
</div>
<div class="row-fluid answer">
<div id="answerdiv_3_<?php echo $i; ?>" onClick="return change_question('<?php echo $correcr_answer[2]; ?>','<?php echo $i; ?>','3');" class="span12 show_cursor"><p><?php echo substr($answerarry[2],0,300);?></p> </div>
</div>