Change style fontSize

by jywglady

HTML

<h2>JavaScript Test</h2>
<p id="demo">JavaScript can change the style of an HTML element.</p>
<button type="button" onclick="myFunction()">Click Me!</button>

JavaScript

var a = 0;
function myFunction() {
  if (a==0) {
    document.getElementById("demo").style.fontSize = '35px';
    a = 1;
  }
  else {
    document.getElementById("demo").style.fontSize = '15px';
    a = 0;
  }
}