Define your mouse over function in javascript(On Page) before you are going to append your div string into page.
function myMouseMover()
{
alert('Mouse Over');
}
while appending string just add the onmouseover attribute to you div as below.
strRet.Append("<div class="col_1_of_3 span_1_of_3 tryathome-container" onmouseover="myMouseover()">")</div>