How correctly check if input is not equal zero

Question

I have simple code, in input user inputs number and it must print the numbers until the input is not equal to zero.

And the problem is when i submit value, page stops responding

Here is how my code looks like:

 window.onload = function() {
    
    var btn = document.getElementsByClassName('btn')[0];
    
    function printInput() {
    	var output = document.getElementsByClassName('output')[0];
    	var input = document.getElementsByClassName('input')[0].value;
    
    	 while(input !== 0) {
         var input = document.getElementsByClassName('input')[0].value;
    		output.innerHTML += input+'<br>'; 
    	}
    }
    	btn.addEventListener('click', printInput);
    
    }

  
    	<input type="text" class="input" maxlength="1">
    	<button class="btn">Submit</button>
    	<div class="output"></div>

Diogo Sgrillo · Accepted Answer · 2017-04-07 14:28:24Z

2

The value property of input is a string.

You must compare with the correct type:

while (input !== '0')

or

while (input != 0)

----- edit -----

Consider changing the while to an if, otherwise it will print any number different of 0 indefinitely.

 window.onload = function() {
    
    var btn = document.getElementsByClassName('btn')[0];
    
    function printInput() {
    	var output = document.getElementsByClassName('output')[0];
    	var input = document.getElementsByClassName('input')[0].value;
    
    	 if(input !== '0') {
         var input = document.getElementsByClassName('input')[0].value;
    		output.innerHTML += input+'<br>'; 
    	}
    }
    	btn.addEventListener('click', printInput);
    
    }

  
    	<input type="text" class="input" maxlength="1">
    	<button class="btn">Submit</button>
    	<div class="output"></div>

answered Apr 7, 2017 at 14:28

Diogo Sgrillo

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1 Comment

Andrew Over a year ago

Thanks i don't know why i decided to use while loops for this easy thing

gurvinder372 · Accepted Answer · 2017-04-07 14:33:37Z

0

You need to make two changes

Change type attribute from text to number
Change from while to if

Demo

window.onload = function() 
{
  var btn = document.getElementsByClassName('btn')[0];
  function printInput() 
  {
    var output = document.getElementsByClassName('output')[0];
    var input = document.getElementsByClassName('input')[0].value;
    if (input !== 0) 
    {
      var input = document.getElementsByClassName('input')[0].value;
      output.innerHTML += input + '<br>';
    }
  }
  btn.addEventListener('click', printInput);
}

<input type="number" class="input" maxlength="1">
<button class="btn">Submit</button>
<div class="output"></div>

answered Apr 7, 2017 at 14:33

gurvinder372

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