title: KnockoutJS change value and text of input on checkbox change event
body: <p>I have a list of skills and when the user checks the skill an input for years will then display if checked. My issue is if user enters a year but then un-checks the skill the value for years is still saved in the observable along with the text on the input. I am not sure if i need to clear the value out with an event handler, subscribe function, or just a ko computed function.</p>
  
  <p><a href="http://jsfiddle.net/bjk964/CQ2CG/2/" rel="nofollow">http://jsfiddle.net/bjk964/CQ2CG/2/</a></p>
  
  <pre><code>&lt;div data-bind="foreach: ApplicationSkills"&gt;                
      &lt;p&gt;
          &lt;span data-bind="text: Skill_SkillTypeName"&gt;&lt;/span&gt;
          &lt;input type="checkbox" data-bind="checked: Skill_Checked" /&gt;
          &lt;span data-bind="visible: Skill_Checked" class="years"&gt;Years:&lt;/span&gt;
          &lt;input type="text" data-bind="value: Skill_Years, visible: Skill_Checked" /&gt;
      &lt;/p&gt;                
  &lt;/div&gt;
  
  var Application = function () {
      this.ApplicationSkills = ko.observableArray();
  };
  
  var ApplicationSkill = function () {
      var self = this;
      this.Skill_SkillTypeID = ko.observable(0);
      this.Skill_Years = ko.observable().extend({ maxLength:2, number:true });
      this.Skill_Checked = ko.observable(false);
      this.Skill_SkillTypeName = ko.observable();
  };
  
  var vm = new Application();
  ko.applyBindings(vm);
  
  var skill = new ApplicationSkill()
  skill.Skill_SkillTypeID(1);
  skill.Skill_SkillTypeName('Data Entry');
  
  vm.ApplicationSkills.push(skill); 
  </code></pre>