Changing array and class values onclick

[AssertiveWD]

I am trying to make a substitute for checkboxes using javascript and php. I am able to pass the variables, but the problem I have is changing the array values and class values depending on if it is selected or not.

Heres the code I threw together. It makes sense to me but I can't seem to get it to work.

<style type="text/css">
#navigationDiv a {
 text-decoration:none;
 display:block;
 color:black;
 margin-bottom:5px;
}
#navigationDiv a.selected {
 text-decoration:underline;
}
#navigationDiv a.unselected {
 text-decoration:none;
}
</style>
<script type="text/javascript">
var check_fields = new Array();
check_fields[0] = "0";
check_fields[1] = "0";
check_fields[2] = "0";
check_fields[3] = "0";
check_fields[4] = "0";
check_fields[5] = "0";
check_fields[6] = "0";
check_fields[7] = "0";
function checked(obj, chk) {
 
if (check_fields[chk] = 1){
check_fields[chk] = 0; 
obj.className = "unselected"; 
}
else {
check_fields[chk] = 1;
obj.className = "selected"; 
}
 
}
</script>
<div id="navigationDiv">
<a href="#" onclick="checked(this, 0)" class="">anchor1</a>
<a href="#" onclick="checked(this, 1)" class="">anchor2</a>
<a href="#" onclick="checked(this, 2)" class="">anchor3</a>
<a href="#" onclick="checked(this, 3)" class="">anchor4</a>
<a href="#" onclick="checked(this, 4)" class="">anchor5</a>
<a href="#" onclick="checked(this, 5)" class="">anchor6</a>
<a href="#" onclick="checked(this, 6)" class="">anchor7</a>
<a href="#" onclick="checked(this, 7)" class="">anchor8</a>
</div>

Thanks for the help

[penders]

if (check_fields[chk] = 1) {
check_fields[chk] = 0;
obj.className = "unselected";
}

You are assigning(=) the value in your IF statement, as opposed to comparing equality(==). So this will always avaluate to true; it will always be 'unselected'.