how to define a textbox value null = 0 and has a value = 1? with javascript

Question

sorry im noob on JS i need help i want to try make a textbox checker that can be check the value of the textbox. when it has a value higher than 0 then has a value = 1, but when it has null value or 0 value then it has a value = 0

this my code

// JavaScript Document

    function check()
        {
            if (document.getElementById('s1').value=="0" 
             || document.getElementById('s1').value==undefined)
            {

                return 0;
                document.getElementById('avr').value = result;
            }
            return 1;
                document.getElementById('avr').value = result;

        }

The .value will be a string. If the field is empty it will be "", not null or undefined. — Pointy
– Pointy, Commented Feb 8, 2017 at 2:17
A return statement exits the function immediately, so the ...('avr').value = result lines in your code can never be executed. Also, if those lines were before the return statements you'd still have a problem because result is not defined (at least, not in the code shown). — nnnnnn
– nnnnnn, Commented Feb 8, 2017 at 2:18
null == 0 and any number higher than 0 == 1? Seem like a boolean value to me, Not sure what you are trying to achieve but I would use Hidden field type checkbox and create a listener to that textbox — Luminous_Dev
– Luminous_Dev, Commented Feb 8, 2017 at 2:21
thx guy's i'm just figure it out,. and i'm just solve my problem a min ago — Hafni D'Kickerz
– Hafni D'Kickerz, Commented Feb 8, 2017 at 2:27

Molly Harper · Accepted Answer · 2017-02-08 02:28:37Z

2

You need to set the element's value before you return. A return statement terminates the execution of a function:

function check()
{
  if (document.getElementById('s1').value === '0' || document.getElementById('s1').value === '') {
    document.getElementById('avr').value = result;
    return 0;
  } else {
    document.getElementById('avr').value = result;
    return 1;
  }
}

edited Feb 8, 2017 at 2:28

answered Feb 8, 2017 at 2:20

Molly Harper

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2 Comments

nnnnnn Over a year ago

The test for undefined won't work. Should be a test for an empty string.

Molly Harper Over a year ago

Sure, just giving the basic answer to his problem.

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