array index searching

findIndexByCol.js

// search through a two dimensional array
Array.prototype.findIndexByCol = function(value,cIdx){
  for (var i=0; i < this.length; i++) {
    // use === to check for Matches. ie., identical (===), ;
    if (this[i][cIdx] == value) {
      //alert(this[i][cIdx]+"===="+value);
      return i;
    }
  }
  return null;
};