Check if a jquery has been loaded or not
Last Updated :
16 Jan, 2023
Given a document, The task is to determine whether JQuery has been loaded or not, If not then load it dynamically using JavaScript. Below are the examples to check:
Approach:
- First, check if it is loaded.
- If not loaded then load it dynamically, create a script element and add properties like(type, src) to it and then finally append it at the end, inside of the head element.
Example 1: In this example, the JQuery is already loaded so the message ‘Script already loaded!’ prints on the screen.
html
< script src =
</ script >
< h1 style = "color:green;" >
GeeksforGeeks
</ h1 >
< p id = "GFG_UP" >
</ p >
< button onClick = "GFG_Fun()" >
click here
</ button >
< p id = "GFG_DOWN" >
</ p >
< script >
var up =
document.getElementById('GFG_UP');
var down =
document.getElementById('GFG_DOWN');
up.innerHTML =
"Click on button to check whether JQuery is loaded";
function GFG_Fun() {
if (!window.jQuery) {
var el = document.createElement('script');
el.type = "text/javascript";
el.src =
document.getElementsByTagName(
'head')[0].appendChild(el);
down.innerHTML = "Script loaded successfully!";
} else {
down.innerHTML = "Script already loaded!";
}
}
</ script >
|
Output:
Check if a jquery has been loaded or not
Example 2: The src attribute of script element is changed to sc. In this example, the JQuery is not loaded so message ‘Script loaded successfully!’ prints on screen after successful loading.
html
< script src =
</ script >
< h1 style = "color:green;" >
GeeksforGeeks
</ h1 >
< p id = "GFG_UP" >
</ p >
< button onClick = "GFG_Fun()" >
click here
</ button >
< p id = "GFG_DOWN" >
</ p >
< script >
var up =
document.getElementById('GFG_UP');
var down =
document.getElementById('GFG_DOWN');
up.innerHTML =
"Click on button to check whether JQuery is loaded";
function GFG_Fun() {
if (!window.jQuery) {
var el =
document.createElement('script');
el.type = "text/javascript";
el.src =
document.getElementsByTagName(
'head')[0].appendChild(el);
down.innerHTML = "Script loaded successfully!";
} else {
down.innerHTML = "Script already loaded!";
}
}
</ script >
|
Output:
Check if a jquery has been loaded or not
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