// Iterate over an array of strings,select the first elements that 
// equalsIgnoreCase the 'matchString' value
var matchString = "MATCHME".toLowerCase();
var rslt = null;
$.each(['foo','bar','matchme'],function(index,value) { 
  if (rslt == null && value.toLowerCase() === matchString) {
    rslt = index;
    return false;
  }
});