Tutorial Clear a File Input
You can just clone it and replace it with itself, with all events still attached.
var input = $("#control");
function something_happens() {
input.replaceWith(input.val('').clone(true));
};
Tutorial Check if jQuery is Loaded
if (typeof jQuery == 'undefined') {
// jQuery IS NOT loaded, do stuff here.
}Tutorial Check if Event was Triggered or Native
$('button').click(function(event, wasTriggered) {
if (wasTriggered) {
alert('triggered in code');
} else {
alert('triggered by mouse');
}
});
$('button').trigger('click', true);Tutorial Check if Element is inside Another Specific Element
Replace the first selector with the child you are testing and the second selector with the parent you are testing for.
if ( $(".child-element").parents("#main-nav").length == 1 ) {
// YES, the child element is inside the parent
} else {
// NO, it is not inside
}Tutorial Check if Element Exists
if ($('#myElement').length > 0) {
// it exists
}Or to make it a fancy function with a callback:
// Tiny jQuery Plugin
// by Chris Goodchild
$.fn.exists = function(callback) {
var args = [].slice.call(arguments, 1);
if (this.length) {
callback.call(this, args);
}
return this;
};
// Usage
$('div.test').exists(function() {
this.append('<p>I exist!</p>');
});
Tutorial Check if Checkbox is Checked
Say that 10 times fast =).
Find out if a single checkbox is checked or not, returns true or false:
$('#checkBox').attr('checked');Find all checked checkboxes:
$('input[type=checkbox]:checked');Tutorial Check for Empty Elements
Do something for each empty element found:
$('*').each(function() {
if ($(this).text() == "") {
//Do Something
}
});TRUE or FALSE if element is empty:
var emptyTest = $('#myDiv').is(':empty');