HTML5 – Guessing number game

In this game, we will familiar with properties placeholder of HTML 5 and javascript function querySelector instead of selectElementById in previous version.

<!doctype html>

<title>Number guessing game</title>

<p id=”output”>I am thinking of a number between 0 and 99.</p>

<input id=”input” type=”text” placeholder=”Enter your guess…”>


<script type=”text/javascript”>

//Game variables

var mysteryNumber = 50;

var playersGuess = 0;

//The input and output fields

var input = document.querySelector(“#input”);

var output = document.querySelector(“#output”);

//The button

var button = document.querySelector(“button”); = “pointer”;

button.addEventListener(“click”, clickHandler, false);

function clickHandler()




function playGame()


playersGuess = parseInt(input.value);

if(playersGuess > mysteryNumber)


output.innerHTML = “That’s too high.”;


else if(playersGuess < mysteryNumber)


output.innerHTML = “That’s too low.”;


else if(playersGuess === mysteryNumber)


output.innerHTML = “You got it!”;




 In this game, when users fill textbox a number, and click on guess button, it will return the result of number. Effect of properties placeholder is take a lot of command in javascript in the pass, now it is so easy.
Finally, in this example, we know how to add an event on a button by command button.addEventListener(“click”, clickHandler, false);

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