How do I check/uncheck a checkbox input or radio button using jQuery

// Check #x $( "#x" ).prop( "checked", true ); // Uncheck #x $( "#x" ).prop( "checked", false );

 

How do I disable/enable a form element using jQuery

// Disable #x $( "#x" ).prop( "disabled", true ); // Enable #x $( "#x" ).prop( "disabled", false );

 

How do I select an element by an ID that has characters used in CSS notation using jQuery

// Does not work:



$( "#some:id" )



 



// Works!



$( "#some\\:id" )



 



// Does not work:



$( "#some.id" )



 



// Works!



$( "#some\\.id" )

How do I determine the state of a toggled element in jQuery

var isVisible = $( "#myDiv" ).is( ":visible" ); var isHidden = $( "#myDiv" ).is( ":hidden" );

I

How do I test whether an element exists in jQuery

$( "#myDiv" ).length

How do I test whether an element has a particular class in jQuery

$( "div" ).click(function() { if ( $( this ).hasClass( "protected" ) ) { $( this ) .animate({ left: -10 }) .animate({ left: 10 }) .animate({ left: -10 }) .animate({ left: 10 }) .animate({ left: 0 }); } });

How do I select elements when I already have a DOM element in jQuery

var myDomElement = document.getElementById( "foo" ); // A plain DOM element. $( myDomElement ).find( "a" ); // Finds all anchors inside the DOM element.