js/libs/ember-1.5.1.js
function(name, value) {
    var properties = this.elementProperties = (this.elementProperties || {});

    if (arguments.length === 1) {
      return properties[name];
    } else {
      properties[name] = value;
    }

    return this;
  }
function(name, value) {
    var properties = this.elementProperties = (this.elementProperties || {});

    if (arguments.length === 1) {
      return properties[name];
    } else {
      properties[name] = value;
    }

    return this;
  }
Adds a property which will be rendered to the element.

@method prop
@param {String} name The name of the property
@param {String} value The value to add to the property
@chainable
@return {Ember.RenderBuffer|String} this or the current property value