jQuery basic help -

I'm sure I'm going to lose some representative points for this, because this is a basic question but I

This element has been given in my document:

(which produces the following markup:

  & quot; Input checked "" checked "id =" isAlwaysValidCheckBox "name = "IsAlwaysValid" onchange = "showHideValidSetList ()" type = "checkbox" value = "true" /> and    
) 
 
 Then this function is using a jQuery selector: 
 
  & lt; script type = "text / javascript" & gt; function ShowHideValidSetList () (checked ($ ("#IsAlwaysValidCheckBox"). {Warning ("IsAlwaysValidCheckBox checked"); Return;} and {Warning ("IsAlwaysValidCheckBox check  
 
 The Javascript must be equal to one by using DOM: 
 
  & quot; Lt; script type = "text / javascript" & gt; function showHideValidSetList (if checked (document.getElementById ("IsAlwaysValidCheckBox")) {Warning ("IsAlwaysValidCheckBox checked"); return;} and {warnings} ("IsAlwaysValidCheckBox is not checked"); Return; }} & Lt; / Script & gt;  
 
 Right? But the Javascript version works as expected, while jQuery always takes the "second" branch, showing it is not actually seeing the status of the checkbox. 
 
 What am I doing? 
 
 Thanks for the effect with me. 
 

Use this:

  if ($ (checkbox control) Instead of:  
  ($ ("#IsAlwaysValidCheckBox") though it looks like the jQuery selector DOM elements (Such as a checkbox), they actually return a jQuery object, in which  checked . You can see it in the uncompressed jquery source code (from) most clearly: 
 
  jQuery.fn = jQuery.prototype = {init: function (selector, context) {// ... / Handle / $ (DOMElement) if (selector.nodeType) {this [0] = selector; This.length = 1; This.context = selector; return it;} // ...}}  
 
 Many interesting jQuery methods (such as animate, atri, html, etc) work on  this.context , whenever you apply, specify or redefine any selector