Can I check for numeric input only in javascript?

Question

I am checking if a input field is empty but would like to check if it is numeric since it is a street address. I only want numeric to be allowed, no alpha even though an address might be like 123a or something else.

I want to keep the same format cause I'm checking other fields in the same function and want it to be the same. Below is what I have for empty field. What is the easiest way to change it to check for numeric only. I was trying if( !isNumeric (numbr.value)) but it isn't working.

var numbr = document.getElementById( "numbr" );
if( numbr.value == "")  {
    error = "Address number must be entered. Numeric only.";
    document.getElementById( "error_para" ).innerHTML = error;
    return false;
    }

Possible duplicate of [HTML Text Input allow only Numeric input](https://stackoverflow.com/questions/469357/html-text-input-allow-only-numeric-input) — Heretic Monkey, Jun 06 '17 at 17:49
Or look at [W3Schools](https://www.w3schools.com/js/js_validation.asp) — Brett Beatty, Jun 06 '17 at 17:50

score 0 · Accepted Answer · answered Jun 06 '17 at 17:53

You could also use parseInt and check if it is NotANumber:

window.onload=function(){

    document.getElementById("numbr").addEventListener("input",function(){
    document.getElementById( "error_para" ).innerHTML = (isNaN(parseInt(this.value,10)))?"Address number must be entered. Numeric only.":"";
    });
    
  };

<input id="numbr">
<div id="error_para"></div>

bre · Answer 2 · 2017-06-06T18:25:51.960

0

I used isNaN and it worked.

var numbr = document.getElementById( "numbr" );
if(isNaN(numbr.value))  {
    error = "Address number must numeric only.";
    document.getElementById( "error_para" ).innerHTML = error;
    return false;
    }

edited Jun 06 '17 at 18:25

answered Jun 06 '17 at 18:08

bre

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Can I check for numeric input only in javascript?

2 Answers2