JSFiddle - React, Tailwind, and code Playground

HTML

<div id="myDiv" >

</div>
<div id="myDiv2" >

</div>

CSS

#myDiv {
  background-color: #440055;
  width: 100px;
  height: 100px;
  
}
#myDiv2 {
  background-color: #234;
  width: 100px;
  height: 100px;
  
}

JavaScript

var toggle = false;
document.getElementById("myDiv").onclick = function(e) {
		var relX = e.clientX;
    var relY = e.clientY;
    if (relX >= relY) {
    	if (toggle)
      	document.getElementById("myDiv2").style.backgroundColor = "#00A";
      else
      	document.getElementById("myDiv2").style.backgroundColor = "#234";
      toggle = !toggle;
    } 
    	
}