Algorithm for subdividing html-elements
A lot of what you are doing is repeated code so you should DRY it out.  For instance, widthPerc is the same code except for the values of widthTop and widthBottom. We can also simply all of our checks by setting them up as vars.  So that could be re-written like this:

var isFirstTwo = !!( i &lt; 3 ); // go ahead and just eval once
var isEven = !!( i % 2 ); // go ahead and just evalonce

//which width value do we want?
var widthDir = ( isFirstTwo ) ? widthTop : widthBottom;
//is it an even number?
widthDir = ( isEven ) ? widthDir : 100 - widthDir;
widthBlock = widthDir * widthBlock / 100;  

divisionObj.widthPerc = widthDir +'%';
divisionObj.width = widthBlock;


This reduces a lot of your code.  You could follow a similar technique for height (it's actually easier than width).

var heightTop = ( isEven ) ? heightTop : (100 - heightTop);
var heightBlock =  heightBlock * heightTop / 100
divisionObj.heightPerc = heightTop + '%';
divisionObj.height = heightBlock;


Hope that helps. I have updated the fiddle. Let me know if you have questions or comments.