DBLookup Undefined Web

I’m hoping someone can give me some advice. I am using javascript. I have a combobox that onChange activates my function to get its value then do a dblookup. My problem I am having is that I keep getting undefined when I use typeof event. I have also tried to just set my variable to the even.srcElement and I get undefined as well. I have pasted the first part of my code below.

Thank you

var objThis;



if(typeof event == "undefined")

alert("error undefined")  



if(typeof event != "undefined")

if(event.srcElement != null){

objThis = event.srcElement;

alert("set objthis")

}

alert(objThis)

*fixed