How do I replace eval in the following script?

Hi
JSLint and Dreamweaver report eval as dangerous. How do I:
1. replace 'eval' in the script
2. move the function outside the loop?

I am learning so any help is appreciated.

/* exported popup_default , popup_help , popup_sitemap , popup_footerlinks */

var matchClass=['popup_default' , 'popup_sitemap','popup_footerlinks', 'popup_help'];
var newwindow = ''
  
    var popup_default = 'width=800,height=640,toolbar=0,menubar=0,location=0,status=1,scrollbars=1,resizable=1,left=250,top=200';  
    var popup_help = 'width=700,height=650,toolbar=0,menubar=0,location=0,status=1,scrollbars=1,resizable=1,left=100,top=100';
    var popup_sitemap = 'width=1000,height=600,toolbar=0,menubar=0,location=0,status=1,scrollbars=1,resizable=1,left=100,top=100';  
    var popup_footerlinks = 'width=800,height=500,toolbar=0,menubar=0,location=0,status=1,scrollbars=1,resizable=1,left=250,top=200';
  
    function pop_ups(){
        "use strict";
        var x = 0;
        var popClass;
        while(x < matchClass.length){
                popClass = "'."+matchClass[x]+"'";
                $(eval(popClass)).click(function() {
                        var popurl = $(this).attr('href');
                        var popupSpecs = $(this).attr('class');
                        var popupName = Math.floor(Math.random()*10000001);
                        newwindow=window.open(popurl,popupName,eval(popupSpecs));
                        return false;
                });                          
        x++;
        }
    }

    $(function() {
    "use strict";
    pop_ups();
    });

Code (markup):

 

Thanks @sarahk It was confusing me. I have it re-writted like this and it seems to work:

/* exported popup_default , popup_help , popup_sitemap , popup_footerlinks */

function makePopup(className, specs) {
    "use strict";
    $('.'+className).click(function(e) {
        e.preventDefault();
        var popupName = Math.floor(Math.random()*10000001);
        window.open(this.href, popupName, specs);
    });
}
var popups = {
    popup_default:     'width=800,height=640,toolbar=0,menubar=0,location=0,status=1,scrollbars=1,resizable=1,left=250,top=200',
    popup_help:        'width=700,height=650,toolbar=0,menubar=0,location=0,status=1,scrollbars=1,resizable=1,left=100,top=100',
    popup_sitemap:    'width=1000,height=600,toolbar=0,menubar=0,location=0,status=1,scrollbars=1,resizable=1,left=100,top=100',
    popup_footerlinks: 'width=800,height=500,toolbar=0,menubar=0,location=0,status=1,scrollbars=1,resizable=1,left=250,top=200'
};

$(function() {
    "use strict";
    for (var key in popups) {
        if(popups.hasOwnProperty(key))
        {
          makePopup(key, popups[key]);
        }
    }
});

Code (markup):