Form Data is not captured correctly

Question

I have tried the below to capture the value "1" on checkbox selection and value "0" on unselection of a checkbox. The Problem I am facing is if I select the checkbox, the value "1" is capturing but if I didn't select the checkbox the value="0" is not captured on form data.

JS:
    <script>
    function setvalue() {
    if (document.getElementById('binary').checked = true) {
       document.getElementById('binary').value='1';
    } else {
        document.getElementById('binary').value='0';
    }
    </script>


HTML:
    <input name="Maximize" id="binary" type="checkbox" value=" ">

Look at the formatting colors. Do you see something wrong? Hint: you're missing the closing } — WillardSolutions, Aug 29 '14 at 16:36
Change `= true` to `=== true`. `=` alone is an assignment operator, so the `value` is **always** being set to `"1"` and will never enter the `else` part — Ian, Aug 29 '14 at 16:36
Good lord, please don't assign stringified numbers. `1` or `0` would be just fine — Sterling Archer, Aug 29 '14 at 16:37
Element values are strings by default, but it's just bad practice to wrap an integer in quotes. It's like `if (x == "true")` where true is now a string instead of a boolean value. Also, cache your elements, so that you don't have to call `document.getElementById("binary")` every single time. — Sterling Archer, Aug 29 '14 at 16:51
Okay then. Thanks. Can you please correct the above code for me? — anandbooklet S, Aug 29 '14 at 16:53
I'm going to leave this one for you. You have plenty of comments to study up from. You got this! — Sterling Archer, Aug 29 '14 at 16:56

score 1 · Answer 1 · answered Aug 29 '14 at 16:42

1

Unchecked checkboxes will not be submitted.

Insert a hidden input before the checkbox:

<input name="Maximize" type="hidden" value="0">
<input name="Maximize" type="checkbox" value="1">

However, it's redundant. When you parse the form-data on serverside simply assume a value of 0 when the variable is not set

answered Aug 29 '14 at 16:42

Dr.Molle

116,463
16
195
201

I have tried this. It is capturing only the "0"s . When I select the checkbox the value "1" is not captured – anandbooklet S Aug 29 '14 at 17:07
captured by what? when you send the form and the checkbox has been checked, 1 will be submitted, otherwise 0 – Dr.Molle Aug 29 '14 at 17:14
No matter I have checked or not, It is always capturing "0"s. Can you please correct my code above and show me how? – anandbooklet S Aug 29 '14 at 17:26
Correct, a script wouldn't help here when the control(form-field) is not successful(and a checkbox is only successful when it's checked). See: [successful controls](http://www.w3.org/TR/html401/interact/forms.html#h-17.13.2). My suggestion uses the hidden input(0) as default and when the checkbox(1) is checked it will overwrite the hidden input. No need for a script. – Dr.Molle Aug 29 '14 at 18:49

score 0 · Answer 2 · answered Aug 29 '14 at 16:47

0

This line

if (document.getElementById('binary').checked = true) {

should be

if (document.getElementById('binary').checked == true) {

or

if (!!document.getElementById('binary').checked) {

no?

answered Aug 29 '14 at 16:47

Patrick Ferreira

1,983
1
15
31

Interesting cast to boolean there. Not many people use it like that – Sterling Archer Aug 29 '14 at 16:54
You can read [this answer](http://stackoverflow.com/questions/9284664/double-exclamation-points#9284677) for more details :-) – Patrick Ferreira Sep 01 '14 at 15:40

Form Data is not captured correctly

2 Answers2