jQuery-väljare


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jQuery vs JavaScript

jQuery skapades 2006 av John Resig. Den designades för att hantera webbläsarinkompatibilitet och för att förenkla HTML DOM-manipulation, händelsehantering, animationer och Ajax.

I mer än 10 år har jQuery varit det mest populära JavaScript-biblioteket i världen.

Men efter JavaScript version 5 (2009) kan de flesta jQuery-verktygen lösas med några rader standard JavaScript:


Hitta HTML-element efter ID

Returnera elementet med id="id01":

jQuery

myElement = $("#id01");

Prova själv →

<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
</head>
<body>

<h2>Finding HTML Elements by Id</h2>
<p id="id01">Hello World!</p>
<p id="id02">Hello Sweden!</p>
<p id="id03">Hello Japan!</p>

<p id="demo"></p>

<script>
$(document).ready(function() {
  var myElements = $("#id01");
  $("#demo").text("The text from the id01 paragraph is: " + myElements[0].innerHTML);
});
</script>

</body>
</html>

JavaScript

myElement = document.getElementById("id01");

Prova själv →

<!DOCTYPE html>
<html>
<body>

<h2>Finding HTML Elements by Id</h2>
<p id="id01">Hello World!</p>
<p id="id02">Hello Sweden!</p>
<p id="id03">Hello Japan!</p>

<p id="demo"></p>

<script>
const myElement = document.getElementById("id01");
document.getElementById("demo").innerHTML = "The text from the id01 paragraph is: " + myElement.innerHTML;
</script>

</body>
</html>

Hitta HTML-element efter taggnamn

Returnera alla <p>-element:

jQuery

myElements = $("p");

Prova själv →

<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
</head>

<body>

<h2>Finding HTML Elements by Tag Name</h2>

<p>Hello World!</p>
<p>Hello Sweden!</p>
<p>Hello Japan!</p>

<p id="demo"></p>

<script>
$(document).ready(function() {
  var myElements = $("p");
  $("#demo").text("The text in the first paragraph is: " + myElements[0].innerHTML);
});
</script>

</body>
</html>

JavaScript

myElements = document.getElementsByTagName("p");

Prova själv →

<!DOCTYPE html>
<html>
<body>

<h2>Finding HTML Elements by Tag Name</h2>
<p>Hello World!</p>
<p>Hello Sweden!</p>
<p>Hello Japan!</p>

<p id="demo"></p>

<script>
const myElements = document.getElementsByTagName("p");
document.getElementById("demo").innerHTML = "The text in the first paragraph is: " + myElements[0].innerHTML;
</script>

</body>
</html>


Hitta HTML-element efter klassnamn

Returnera alla element med class="intro".

jQuery

myElements = $(".intro");

Prova själv →

<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
</head>
<body>

<h2>Finding HTML Elements by Class Name</h2>

<p class="intro">Hello World!</p>
<p class="intro">Hello Sweden!</p>
<p class="intro">Hello Japan!</p>

<p id="demo"></p>

<script>
$(document).ready(function() {
  var myElements = $(".intro");
  $("#demo").text("The first paragraph with class='intro' is: " + myElements[0].innerHTML);
});
</script>

</body>
</html>

JavaScript

myElements = document.getElementsByClassName("intro");

Prova själv →

<!DOCTYPE html>
<html>
<body>

<h2>Finding HTML Elements by Class Name</h2>
<p class="intro">Hello World!</p>
<p class="intro">Hello Sweden!</p>
<p class="intro">Hello Japan!</p>

<p id="demo"></p>

<script>
const myElements = document.getElementsByClassName("intro");
document.getElementById("demo").innerHTML = "The first paragraph with class='intro' is: " + myElements[0].innerHTML;
</script>

</body>
</html>

Hitta HTML-element med CSS-väljare

Returnera en lista över alla <p>-element med class="intro".

jQuery

myElements = $("p.intro");

Prova själv →

<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
</head>
<body>

<h2>Finding HTML Elements by Query Selector</h2>

<p class="intro">Hello World!</p>
<p class="intro">Hello Sweden!</p>
<p class="intro">Hello Japan!</p>

<p id="demo"></p>

<script>
$(document).ready(function() {
  var myElements = $("p.intro");
  $("#demo").text("The first paragraph with class='intro' is: " + myElements[0].innerHTML);
});
</script>

</body>
</html>

JavaScript

myElements = document.querySelectorAll("p.intro");

Prova själv →

<!DOCTYPE html>
<html>
<body>

<h2>Finding HTML Elements by Query Selector</h2>
<p class="intro">Hello World!</p>
<p class="intro">Hello Sweden!</p>
<p class="intro">Hello Japan!</p>

<p id="demo"></p>

<script>
const myElements = document.querySelectorAll("p.intro");
document.getElementById("demo").innerHTML = 
"The first paragraph with class='intro' is: " + myElements[0].innerHTML;
</script>

</body>
</html>