3 examples of jQuery is() function usage_jquery

jQuery provides the is() method to easily determine whether an element is visible, hidden, and selected.

1. Determine whether the element is hidden

The div element in the following html is hidden:

Copy the code The code is as follows:

 

You can’t see me

 

2. Determine whether the checkbox is selected

In jquery, you can use xx.is(':checked') to determine whether checkbox and radiobutton are selected. Test html as follows

Copy code The code is as follows:

  chkChecked
chkNoChecked

 

3. Determine whether a certain style is used

Copy the code The code is as follows:

//Note that the first div appears here

//Note that the second div appears here

//Note that the third div appears here

//Note that the fourth div appears here

Peter

//Note that the fifth div appears here

//Note that the 6th div appears here

<script><BR> $("div").one('click', function () { //$("div").one represents attaching an event to the div element, <BR>//You can also attach multiple events, such as click or mouseout to execute something at the same time <BR> if ($(this ).is(":first-child")) { //is function comes into play, is(":first-child") represents <BR> //Judge whether this div is the first div to appear<BR> $ ("p").text("It's the first div."); //The difference between text and html is whether it supports html tags <BR> // If you write an alert in it at this time, it will not be executed <BR> } else if ($(this).is(".blue,.red")) { //Determine whether the div has a blue or red class<BR> $("p").text("This is blue or red Red div");<BR> } else if ($(this).is(":contains('Peter')")) { //Determine whether the word Peter exists in the div<BR> $("p" ).text("It's Peter!");<BR> } else {<BR> } $("p").html("It's nothing <em>special.");<BR> }<BR> $("p").hide().slideDown("slow"); //This is an animation effect that slowly displays the content of p<BR> $(this).css({"border-style" : "inset", cursor:"default"});<BR> });<BR></script>