How can I assign div’s HTML to a title attribute of an image

How can I assign div's HTML to a title attribute of an image

I have an image with the following HTML:
<img id='ToolTipImage' class='tooltip'
src='/files/404048/93171/Info-32.png' title='' style='margin-top:3px;
margin-left:4px;' />
<div id='AssessmentsGrid'> </div>
I am using tipTip as a tooltip and want to assign div (AssessmentsGrid)'s
html to the title attribute of my image above. Initially div
(AssessmentsGrid) is empty and then I run a query and populate it.