Add Attribute to Child Elements in component

This is the component I try to add in Editor. <div class="page"> <div class="col1"></div> <div class="col2"></div> </div> After adding those components I try to add some computed values to the elements like this, element.on('component:add',function(ele){ ele.addAttributes({ 'data-top' : topOffset, 'data-left' : leftOffset, }); editor.render();// For render Updated html }); But, this code only update the .page component only. How Can I add those attr into .col1,.col2 elements inside .page component ?