Image Rollover - Capture Event Action Without Passing To Function

I'm really just playing around, trying to be as unobtrusive as possible, meaning that I didn't want to just do the standard on mouseover/onmouseout event actions inline in my html. My attempt was relatively close, I just need a way to be able to capture the event action without passing it into a function?

Code:
<script>
var getTabs = function(){
var allTabs = document.getElementsByTagName("div");
for (var i=0;i<allTabs.length;i++){
if (allTabs[i].className == "tabs"){
if (allTabs[i].id == this.id){
if (this.onmouseover != null){
//alert("MouseOVer");
document.getElementById(this.id).style.backgroundColor = "#465D77";
} else if (this.onmouseout != null) {
//alert("MouseOOut");
document.getElementById(this.id).style.backgroundColor = "#1a3757";
}}}}}
onload = function(){
document.getElementById("tabHR").onmouseover = getTabs;
document.getElementById("tabHR").onmouseout = getTabs;
}
</script>

HTML Code:
<!-- Begin Tabs Container -->
<div id="tabsContainer">
<div id="tabGlobal" class="tabsActive">
Home
</div>
<div id="tabHR" class="tabs">
HR Edit
</div>
<div id="tabReports" class="tabs">
Reporting
</div>
<div id="tabData" class="tabs">
Data
</div>
</div>
<!-- End Tabs Container -->