p5.js Element hasClass() Method

Last Updated : 20 Nov, 2020

The hasClass() method of p5.Element in p5.js is used to check if the specified class is already present in the element. It returns a boolean value denoting if the class was present or not. An element can have multiple classes assigned to it.

Syntax:

hasClass( class )

Parameters: This function accepts a single parameter as mentioned above and described below.

class: It is a string that denotes the class to be checked.

Example: The example below illustrates the hasClass() method in p5.js

<html> 
  
<head> 
    <script src= 
"https://cdn.jsdelivr.net/npm/p5@0.10.2/lib/p5.js"> 
    </script> 
    <script src="sketch.js"></script> 
</head> 
  
<body></body> 
  
</html> 

Javascript code: The following code is used for the above “sketch.js” file.

Javascript

function setup() { 
  createCanvas(600, 300); 
  textSize(18); 
    
  // Create a new p5.Element 
  tmpElement = createElement("div"); 
  
  text("Click on the buttons to add, remove " + 
       "or check the class of the element", 20, 20); 
  
  setBtn =  
    createButton("Add color class to element"); 
    setBtn.position(30, 40); 
    setBtn.mouseClicked(() => { 
    tmpElement.addClass("color"); 
  }); 
  
  removeBtn = 
    createButton("Remove color class from element"); 
  removeBtn.position(30, 80); 
  removeBtn.mouseClicked(() => { 
    tmpElement.removeClass("color"); 
  }); 
  
  showBtn = createButton("Check if class exists"); 
  showBtn.position(30, 120); 
  showBtn.mouseClicked(checkClass); 
} 
  
function checkClass() { 
  clear(); 
  // Check if the given class exists 
  let hasC = tmpElement.hasClass("color"); 
  
  text("hasClass('color') gives the output: " + 
       hasC, 20, 180); 
  
  text("Click on the buttons to add, remove or " + 
       "check the class of the element", 20, 20); 
} 