HTML DOM setAttribute() method

setAttribute()The method sets the attribute value of the specified element.

If the attribute already exists, update the value; otherwise, a new attribute will be added using the specified name and value.

UsageremoveAttribute()The method removes an attribute from an element.

Syntax:

element.setAttribute(name, value)

Example

var x = document.getElementsByTagName("H"1")[0];
x.setAttribute("class", "demo");

All browsers fully support the setAttribute() method:

Method
setAttribute()	Is	Is	Is	Is	Is

Parameter	Description
name	A string that specifies the name of the attribute to be set to its value
value	A string containing the value to be assigned to the attribute

Change the input button to an input field:

Example

document.getElementsByTagName("input")[0].setAttribute("type", "text");

Set the value of the href attribute of the anchor element:

Example

var x = document.getElementsByTagName("a")[0];
x.setAttribute("href", "https:")//www.oldtoolbag.com/CSS3/");