How to check if an element DOM exists
Be careful when you wish if an element DOM exists. If you use:
if ( $("#my-id") ){
// exists?
}
This method doesn’t work because jQuery will return an [Object object]
even if the element doesn’t exist. We may use a couple of methods to be sure that an element exists:
if ( $("#my-id").length > 0){
// ok, exists
}
// or
if ( $("#my-id").length ){
// ok, exists
}
// or
if ($("#my-id").size() ) {
// ok, exists
}
// or
if ($("#my-id")[0] ) {
// ok, extsts
}
How to get jQuery version
$().jquery;
// or
jQuery.fn.jquery;
How to fire an event
// For example, add an event
$('#bottone').click(
function() {
alert( 'Hello...' );
}
);
// Direct fire
$('#bottone').click();
// or
$('#bottone').trigger('click');