jQuery.Model.prototype.errors  function     

Runs the validations on this model. You can also pass it an array of attributes to run only those attributes. It returns nothing if there are no errors, or an object of errors by attribute.

To use validations, it's suggested you use the model/validations plugin.

$.Model("Task",{
  init : function(){
    this.validatePresenceOf("dueDate")
  }
},{});

var task = new Task(),
    errors = task.errors()

errors.dueDate[0] //-> "can't be empty"