JavaScript is full-featured all by itself
but there are many tasks for which a lot needs to be done
and are not in the core language
jQuery
immediately upon importing jquery-3.2.1.js
, the variable jQuery
will be accessible!
<head>
<meta charset="UTF-8" />
<title>Page with a style sheet</title>
<script src="http://cmpt165.csil.sfu.ca/
js/jquery-3.2.1.js" />
</head>
jquery-3.2.1.js
alert
function call
here
jQuery
setup = function() {
all_paragraphs = jQuery('p')
all_paragraphs.click(say_hello)
}
jquery_doc = jQuery(document)
jquery_doc.ready(setup)
"p"
given to the jQuery function is a selector (or jQuery selector to be more specific)
jQuery
selectorsjQuery
selectors vs. CSS SelectorsjQuery
extends things so you can specify things in jQuery
that won't work in CSS,
for more details look at here
jQuery
selector, what it gives back is a jQuery
object
p_click = function() {
jQuery('#changeme').html('Somebody clicked me.')
}
h1_hover = function() {
jQuery('#changeme').html('Mouse <em>over</em> the <h1>.')
}
setup = function() {
jQuery('#changeme').click(p_click)
jQuery('h1').mouseover(h1_hover)
}
jQuery(document).ready(setup)
jQuery
event attaching mechanism