JSFiddle - React, Tailwind, and code Playground

HTML

<p id="color">yellow</p>   
<input type="text" id="content">

JavaScript

$("#content").keyup(function(){

	//alert($(this).val());
    
     
		var cntLength = $("#content").val().length;
	 	 var getTxt=$(this).val();
		 var basecolor=$("#color").text();
       var bcolorLength=$("#color").text().length;
 		
  if(basecolor.substring(0,cntLength)==getTxt.substring(0,cntLength))
  {
        $("#color").html("<b>" + basecolor.substring(0,cntLength) +"</b>"+basecolor.substring(cntLength,bcolorLength));

  }



     if(getTxt==basecolor)
     {
     $('body').css('background-color',basecolor);
     }
     else
     {
     $('body').css('background-color','white');
     }
  


});