Accessing parent and child controls

This recipe demonstrates how to access parent and child elements in the DOM when performing client-side validation of a sample form. The constructs used in this example are summarized as follows:

Construct	Type	Description
$("#identifier")	jQuery selector	This selects an element based on its ID
$("html_tag")	jQuery selector	This selects all elements with the specified HTML tag
$(this)	jQuery object	This refers to the current jQuery object
.addClass()	jQuery method	This adds the specified CSS class to each matched element
:checked	jQuery selector	This selects checked input elements
.children()	jQuery method	This returns the immediate descendant element of the matched elements
.each()	jQuery method	This iterates over the matched elements and executes a function for each element
event.preventDefault()	jQuery method	This prevents the default action of the event from being triggered
.find() ...