Pb with css('top')

Hi all,

I just want to adjust conditionally the vertical position of the label text element (intitule1) of some instances of the same symbol :

var intitule1 = case_symb.$('produit1');

if (entree.sR2 == "")

{

  var intiTop = parseInt( intitule1.css( 'top'));   // 107

  intiTop = (intiTop +5) +'px';                           // "112px" : ok

  intitule1.css( 'top', intiTop);                          // doesn't work

}

What am I doing wrong ? Any ideas ? Thanks.

Gil