Use this method, if you want to set alternate color of div without parameter.

function SetAlternateColor() {
 var count = 0;
$j('#MainDiv > div').each(function() {
$j('#' + this.id).removeClass("BkgndClass");
if (count % 2 != 0)
$j('#' + this.id).addClass("BkgndClass");
count = count + 1;
});
return count;
 }

Use this method, if you want to set alternate color of div with parameter.

function SetAlternateColor(empId) {
var count = 0;
 $j('# MainDiv_' + empId + ' > div').each(function() {
$j("#" + this.id).removeClass("BkgndClass");
if (count % 2 != 0) {
$j("#" + this.id).addClass("BkgndClass");
}
count = count + 1;
});
return count;
 }