//In older versions you could use attr.
//As of jQuery 1.6 you should use prop instead:
$("#target :input").prop("disabled", true);
//To disable all form elements inside 'target'. See :input:
//Matches all input, textarea, select and button elements.
//If you only want the <input> elements:
$("#target input").prop("disabled", true);
// Disable #x
$( "#x" ).prop( "disabled", true );
// Enable #x
$( "#x" ).prop( "disabled", false );
//jQuery 1.6+ use:
$("#inputID").prop('disabled', true); //disable
$("#inputID").prop('disabled', false); //enable
//jQuery 1.5 and below use:
$("#inputID").attr('disabled','disabled'); //disable
$("#inputID").removeAttr('disabled'); //enable
$( "#x" ).prop( "disabled", true );
// Enable #x
$( "#x" ).prop( "disabled", false );