Hello,

I am making a price per seat map for a fictional website for my school.
The problem is that I need to let people see the total price but I don't know how to do it.

<script type="text/javascript">
var totaal=0;
function fm10(){
var chkBox=document.getElementById('m10');
if(chkBox.checked)
{
document.getElementById('tm10').innerHTML = '7,50';


}else{
document.getElementById('tm10').innerHTML = '';


}
}

function fm9(){
var chkBox=document.getElementById('m9');
if(chkBox.checked)
{
document.getElementById('tm9').innerHTML = '7,50';


}else{
document.getElementById('tm9').innerHTML = '';


}
}

function fm8(){
var chkBox=document.getElementById('m8');
if(chkBox.checked)
{
document.getElementById('tm8').innerHTML = '7,50';


}else{
document.getElementById('tm8').innerHTML = '';


}
}

function fm7(){
var chkBox=document.getElementById('m7');
if(chkBox.checked)
{
document.getElementById('tm7').innerHTML = '7,50';


}else{
document.getElementById('tm7').innerHTML = '';


}
}

function fm6(){
var chkBox=document.getElementById('m6');
if(chkBox.checked)
{
document.getElementById('tm6').innerHTML = '7,50';


}else{
document.getElementById('tm6').innerHTML = '';


}
}

function fm5(){
var chkBox=document.getElementById('m5');
if(chkBox.checked)
{
document.getElementById('tm5').innerHTML = '7,50';


}else{
document.getElementById('tm5').innerHTML = '';


}
}

function fm4(){
var chkBox=document.getElementById('m4');
if(chkBox.checked)
{
document.getElementById('tm4').innerHTML = '7,50';


}else{
document.getElementById('tm4').innerHTML = '';


}
}

function fm3(){
var chkBox=document.getElementById('m3');
if(chkBox.checked)
{
document.getElementById('tm3').innerHTML = '7,50';


}else{
document.getElementById('tm3').innerHTML = '';


}
}

</script>
<div id="zalen1plattegrond" <?php echo $zaal1hidden;?>>
<form id="zaal1plattegrond" method="post" action="IDEAL_test/klantgegevens.php" >
<form id="zaal1plattegrond" method="post" action="IDEAL_test/klantgegevens.php" >
<table width="400" >
<tr align="center">
<td></td>
<td></td>
<td bgcolor="#c77f68"><input type="checkbox" id="m10" onClick="fm10()" name="stoel[]" value="cl3m10" <?php if($rcl3m10==true){ echo $disable;}?>></td>
<td bgcolor="#c77f68"><input type="checkbox" id="m9" onClick="fm9()" name="stoel[]" value="cl3m9" <?php if($rcl3m9==true){ echo $disable;} ?>></td>
<td bgcolor="#c77f68"><input type="checkbox" id="m8" onclick="fm8()" name="stoel[]" value="cl3m8" <?php if($rcl3m8==true){ echo $disable;} ?>></td>
<td bgcolor="#c77f68"><input type="checkbox" id="m7" onclick="fm7()" name="stoel[]" value="cl3m7" <?php if($rcl3m7==true){ echo $disable;} ?>></td>
<td bgcolor="#c77f68"><input type="checkbox" id="m6" onclick="fm6()" name="stoel[]" value="cl3m6" <?php if($rcl3m6==true){ echo $disable;} ?>></td>
<td bgcolor="#c77f68"><input type="checkbox" id="m5" onclick="fm5()" name="stoel[]" value="cl3m5" <?php if($rcl3m5==true){ echo $disable;} ?>></td>
<td bgcolor="#c77f68"><input type="checkbox" id="m4" onclick="fm4()" name="stoel[]" value="cl3m4" <?php if($rcl3m4==true){ echo $disable;} ?>></td>
<td bgcolor="#c77f68"><input type="checkbox" id="m3" onclick="fm3()" name="stoel[]" value="cl3m3" <?php if($rcl3m3==true){ echo $disable;} ?>></td>
<td></td>
<td></td>
</tr> <!-- M -->
<tr align="center">
This is what I have so far