Click a element to trigger the event of B element to be identified under IE8 as a element _javascript technique

var Menuurl = $ (EVENTSRC). attr ("Navurl"); 
if (Menuurl = = undefined) {//compatible IE8 $ (EVENTSRC) identification error, take first 
//Menuurl = $ ("#left_menu-small Li:first A"). attr (" Navurl "); 
var browser = getieversion (); 
if (browser = = "IE8") {//compatible IE8 $ (EVENTSRC) Recognition error, take the first 
Menuurl = $ ("#left_menu-small Li:first A"). attr ("Navurl"); 

For example: Click a element trigger B element event, according to the reason of the event source is B element, in the IE8 will be recognized as a element, in other browsers no problem, temporarily no good solution, I am here just IE8 under the manual to get B element