Check if the input is all numbers html javascript

Question

I need to make sure that the user inputs all numbers not letters in weight, height and age

function calculate(){
        var w= document.getElementById("weight").value;
        var h=document.getElementById("height").value;
        var a=document.getElementById("age").value;

        //if all numbers enter loop
        var height= Number(h);
        if(document.one.gender[0].checked)
        {var ans= 50+ (height/2) ;}
        else
        {var ans=46+ (height/2) ;}

        alert(ans);
        }
       // else alert("enter numbers only");

Always welcome! Could you please upvote and accept my answer below? :) — Timur Osadchiy
– Timur Osadchiy, Commented Mar 2, 2015 at 17:34

Timur Osadchiy · Accepted Answer · 2015-03-02 17:28:26Z

1

You can check the following way:

if (isNaN(document.getElementById("weight").value)){
// Not number
} else {
// It is number
}

Edited code:

function calculate(){
    var w= document.getElementById("weight").value;
    var h=document.getElementById("height").value;
    var a=document.getElementById("age").value;

    if (isNaN(w) || isNaN(h) || isNaN(a)) {
      alert("Please ensure that weight, height and age are integers");
      return;
    }

    //Your code if all numbers

}

edited Mar 2, 2015 at 17:28

answered Mar 2, 2015 at 17:22

Timur Osadchiy

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Timur Osadchiy Over a year ago

Always welcome! Could you please upvote and accept my answer? :)

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