I have a HTML see below

here i trying to get all Li whose has class selectedLi,
I am trying
$("#coverage_ul li .selectedLi");
but this was not returning any thing
Remove the space between li and .selectedLi:
$('#coverage li.selectedLi')
As it stands it's looking for a descendent of the li with that class, not an li with that class.
(FWIW, using selectedLi as the class name is probably a little over-the-top - it would be quite normal to just use selected and rely on the fact that the element is a <li> per the selector to choose the appropriate styles).
try this
$("#coverage_ul li.selectedLi")
//^^^^^^^^^^^remove space here between li and .selectedLi
if you use any selector with class then
first write element type then its (class or id) in your case like below
elementtype class or id =last result
li .selectedLi =li.selectedLi
$("#coverage_ul .selectedLi");will work as well.