Making random not so random

Fiddle

This is what I currently have. It's working, but I'd like to edit the random function so that the divs (this is just a mockup, there will be many, many more!) would be "evenly distributed" according to the browser's width, if that makes any sense. In a way that no horizontal scroll bar would ever be necessary!

I think this is a good example. Click the Designer's name (top left corner) and you'll see what I mean. Notice how those folders always use the whole window no matter how small or big it is? I want to mimic that behavior... I just don't know to go about it... edit the current script? a totally different approach?

Any input would be highly appreciated. Thanks.

html

<div id="box1" class="boxes">
<div id="text1">&nbsp;&nbsp;Lorem Ipsum Dolor Sit Amet&nbsp;&nbsp;</div>
</div>

<div id="box2" class="boxes">
<div id="text2">&nbsp;&nbsp;Lorem Ipsum Dolor Sit Amet&nbsp;&nbsp;</div>
</div>

<div id="box3" class="boxes">
<div id="text3">&nbsp;&nbsp;Lorem Ipsum Dolor Sit Amet&nbsp;&nbsp;</div>
</div>

<div id="box4" class="boxes">
<div id="text4">&nbsp;&nbsp;Lorem Ipsum Dolor Sit Amet&nbsp;&nbsp;</div>
</div>

css

.boxes {
    position: absolute;
}

#text1 {
    color: white;
    font-family: "Times", Times New Roman, serif;
    font-size: 16px;
    font-weight: bold;
    line-height: 24px;
    background-color: black;
}

    #text2 {
    color: white;
    font-family: "Times", Times New Roman, serif;
    font-size: 16px;
    font-weight: bold;
    line-height: 24px;
    background-color: blue;
}

#text3 {
    color: white;
    font-family: "Times", Times New Roman, serif;
    font-size: 16px;
    font-weight: bold;
    line-height: 24px;
    background-color: green;
}

#text4 {
    color: white;
    font-family: "Times", Times New Roman, serif;
    font-size: 16px;
    font-weight: bold;
    line-height: 24px;
    background-color: red;
}

javascript

var boxDims = new Array();

function setRandomPos(elements,x,dx){
  elements.each(function(){
    var conflict = true;
    while (conflict) {
        fixLeft=(Math.floor(Math.random()*x)*10) + dx;
        fixTop = (Math.floor(Math.random()*40)*10) + 180;
        $(this).offset({
            left: fixLeft,
            top: fixTop
        });
        var box = {
            top: parseInt(window.getComputedStyle($(this)[0]).top),
            left: parseInt(window.getComputedStyle($(this)[0]).left),
            width: parseInt(window.getComputedStyle($(this)[0]).width),
            height: parseInt(window.getComputedStyle($(this)[0]).height)
        }
        conflict = false;
        for (var i=0;i<boxDims.length;i++) {
            if (overlap(box,boxDims[i])) {
                conflict = true;
                break;
            } else {
                conflict = false;
            }                   
        }
    }
    boxDims.push(box)

  });
}

function overlap(box1,box2) {
  var x1 = box1.left
  var y1 = box2.top;
  var h1 = box1.height;
  var w1 = box1.width;
  var b1 = y1 + h1;
  var r1 = x1 + w1;
  var x2 = box1.left;
  var y2 = box1.top;
  var h2 = box1.height;
  var w2 = box1.width;
  var b2 = y2 + h2;
  var r2 = x2 + w2;

  var buf = 24;

  if (b1 + buf < y2 || y1 > b2 + buf || r1 + buf < x2 || x1 > r2 + buf) return false;
  return true;
}

setRandomPos($(".boxes"),40,40);