Example register for click delegation

click-register.js

function ClickRegister(global, parent, debug) {
  var parent   = parent || document,
      debug    = !!debug,
      register = [];

  var action = function (event) {
    var target = event.target || event.srcElement;

    if (debug) {
      console.group("click register debugging");
      console.log(event);
      console.log(target);
      console.groupEnd();
    }

    for (var i = register.length - 1; i >= 0; i--) {
      if (target.matches(register[i].condition)) {
        register[i].func.apply(this, [event, target]);
        break; // Are we allowing multiple events per condition?
      }
    }
  };

  if (parent.addEventListener) {
    parent.addEventListener("click", action, false);
  } else if (parent.attachEvent) {
    parent.attachEvent("onclick", action);
  } else {
    throw "Unable to add event listener to parent element";
  }

  return {
    register: function (condition, func) {
      if (typeof condition !== "string") {
        throw "condition must be a string";
      }

      if (func.length !== 2) {
        throw "argument 2 must be an instance of function that accepts two arguments (event, target)";
      }

      register.push(
        {
          condition: condition,
          func: func
        }
      );
    },
    deregister: function (condition) {
      register = register.filter( function (v, k) {
        return v.condition !== condition;
      }, condition);
    },
    getAll: function () {
      return register;
    }
  };
}