🗊Презентация JQuery. Converting Numbers to Strings

Lecture 9 JQuery Senior-lecturer: Sarsenova Zh.N.

Converting Numbers to Strings The global method String() can convert numbers to strings. It can be used on any type of numbers, literals, variables, or expressions:

The Number method toString() does the same.

jQuery  jQuery is a JavaScript Library. jQuery greatly simplifies JavaScript programming The purpose of jQuery is to make it much easier to use JavaScript on your website.

JQuery The jQuery library contains the following features: HTML/DOM manipulation CSS manipulation HTML event methods Effects and animations AJAX Utilities Many of the biggest companies on the Web use jQuery, such as: Google Microsoft IBM Netflix

Adding jQuery to Your Web Pages There are several ways to start using jQuery on your web site. You can: Download the jQuery library from jQuery.com Include jQuery from a CDN, like Google Place the downloaded file in the same directory as the pages where you wish to use it.

jQuery CDN Both Google and Microsoft host jQuery. To use jQuery from Google or Microsoft, use one of the following: Google CDN: Microsoft CDN:

jQuery Syntax The jQuery syntax is tailor-made for selecting HTML elements and performing some action on the element(s). A $ sign to define/access jQuery A (selector) to "query (or find)" HTML elements A jQuery action() to be performed on the element(s)

Example $(this).hide() - hides the current element. $("p").hide() - hides all <p> elements. $(".test").hide() - hides all elements with class="test". $("#test").hide() - hides the element with id="test".

The Document Ready Event This is to prevent any jQuery code from running before the document is finished loading (is ready). It is good practice to wait for the document to be fully loaded and ready before working with it. This also allows you to have your JavaScript code before the body of your document, in the head section.

The shorter method

jQuery Selectors jQuery selectors are used to "find" (or select) HTML elements based on their name, id, classes, types, attributes, values of attributes and much more.

The element Selector The jQuery element selector selects elements based on the element name. You can select all <p> elements on a page like this:

Example

The #id Selector The jQuery #id selector uses the id attribute of an HTML tag to find the specific element.

The .class Selector The jQuery class selector finds elements with a specific class.

More Examples of Jquery Selector

jQuery Event Methods All the different visitor's actions that a web page can respond to are called events.

jQuery Syntax For Event Methods

Example

Events mouseenter()- The function is executed when the mouse pointer enters the HTML element: mouseleave() - The function is executed when the mouse pointer leaves the HTML element: mousedown()- The function is executed, when the left, middle or right mouse button is pressed down, while the mouse is over the HTML element: mouseup()- The function is executed, when the left, middle or right mouse button is released, while the mouse is over the HTML element: hover() - The hover() method takes two functions and is a combination of the mouseenter() and mouseleave() methods. focus()- The function is executed when the form field gets focus: blur() - The blur() method attaches an event handler function to an HTML form field. The function is executed when the form field loses focus:

The on() Method The on() method attaches one or more event handlers for the selected elements. Attach a click event to a <p> element:

Example

jQuery Effects - Hide and Show With jQuery, you can hide and show HTML elements with the hide() and show() methods: Syntax:

Example

 Hide and Show with speed The optional speed parameter specifies the speed of the hiding/showing, and can take the following values: "slow", "fast", or milliseconds.

jQuery toggle() With jQuery, you can toggle between the hide() and show() methods with the toggle() method. Shown elements are hidden and hidden elements are shown: Syntax: $(selector).toggle(speed,callback);

jQuery Effects - Fading With jQuery you can fade an element in and out of visibility. jQuery has the following fade methods: fadeIn() - is used to fade in a hidden element. fadeOut() - is used to fade out a visible element. fadeToggle() - toggles between the fadeIn() and fadeOut() methods. fadeTo() -  allows fading to a given opacity (value between 0 and 1).

Example of Fading

jQuery Effects - Sliding The jQuery slide methods slide elements up and down. With jQuery you can create a sliding effect on elements. jQuery has the following slide methods: slideDown() slideUp() slideToggle() Syntax: $(selector).slideDown(speed,callback);

Example of Sliding

jQuery Animations - The animate() Method The jQuery animate() method is used to create custom animations. Syntax: $(selector).animate({params},speed,callback);

Example of animate() method

scrollTop() Description: sets or returns the vertical scrollbar position for the selected elements. When the scrollbar is on the top, the position is 0. When used to return the position: This method returns the vertical position of the scrollbar for the FIRST matched element. $(selector).scrollTop() - Return vertical scrollbar position: $(selector).scrollTop(position) - Set vertical scrollbar position:

Example of scrollTop() method

From w3schools.com read about JQuery