Passing parameters to IFRAME with multiple conditions

Hi,

I am a novice at this and I got this code online and tweaked it a little. But it doesn't work. I am trying to pass 2 of 3 possible variables to an inline frame. Var_1 is always passed through, and either var_2 or var_3. The following is a sample of the code I am currently using; i have changed the variable names to make it easier to follow.

<iframe name="Shop" id="Shop" width="100%" height="1875" src="shop.php?"></iframe>
<script type="text/javascript">
if(location.search.length>0){
    var search = location.search;
    search = search.replace(/\?/,'');
   
    var searchAttributes = search.split('&');
    for(var no=0;no<searchAttributes.length;no++){
        var items = searchAttributes[no].split('=');
        eval("var "+items[0]+" = '"+items[1]+"';");
    }
    if(Variable_1 && Variable_2){
        document.getElementById('Shop').src='shop.php?var_1='+Variable_1+'&var_2='+Variable_2;
                 }
    else { if(Variable_1 && Variable_3){
        document.getElementById('Shop').src='shop.php?sid='var_1='+Variable_1+'&search[text]='+Variable_3;
                 };}
}else{
    document.getElementById('Shop').src='blank.htm';

}
</script>

It appears that I a able to pass Variable_1 and Variable_2 into the inline frame without a problem. However, in cases where Variable_3 is used the variable is not passed through...and the inline frame only lands at shop.php?. I think it is something to do with the if else statement, but I looked it over a thousand times and I can't seem to figure it out. Can anyone help be figure out what's wrong with this code? Any help would be much appreciated.

Thanks