jQuery - variable scope issue "value assigned is never used"

Question

I'm trying to make a radio button uncheck when clicked again and the below code only works for the first uncheck.

lastChecked = null; inside the if statement gives warning that "value assigned is never used" and I suspect that this is the cause of issue which I can't figure out.

What can be done to arrange this variable in correct scope?

var lastChecked = null;

$j('input[name=radio-group]:radio').click(function(){
    if (lastChecked == this) {
        this.checked = false;
        lastChecked = null;
    }
    lastChecked = this;
});

will always lastChecked = this;

Deepak Ingole
– Deepak Ingole

2014-09-19 05:51:49 +00:00
Commented Sep 19, 2014 at 5:51 — Deepak Ingole
– Deepak Ingole, Commented Sep 19, 2014 at 5:51

vikrant singh · Accepted Answer · 2014-09-19 07:23:02Z

1

There could be more then one radio button ,but you are handling all of the with only single variable lastChecked

Try using .data() method

    $('input[name=radio-group]:radio').click(function () {
    $('input[name=radio-group]:radio').not($(this)).data("lastChecked",false);
    if (!$(this).data("lastChecked")) {
        $(this).data("lastChecked", (this.checked = true))
    } else {
        $(this).data("lastChecked", (this.checked = false))
    }
});

DEMO

answered Sep 19, 2014 at 7:23

vikrant singh

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1 Comment

Seong Lee Over a year ago

Thank you. Looks very promising. I will give it a try.

Bhushan Kawadkar · Accepted Answer · 2014-09-19 05:51:53Z

1

you should use else to assigne value lastChecked = this;, otherwise lastChecked variable have value of clicked radio button always and never get null

$j('input[name=radio-group]:radio').click(function(){
    if (lastChecked == this) {
        this.checked = false;
        lastChecked = null;
    }
    else
   {
    lastChecked = this;
    }
});

Also instead of assigning radio button to variable, assign radio button value to it. This will help you better to debug your script like putting alert and check which radio selected etc. see below code

$j('input[name=radio-group]:radio').click(function(){
  if (lastChecked == this.value) {
     this.checked = false;
     lastChecked = null;
   }
   else
   {
     lastChecked = this.value;
   }
});

answered Sep 19, 2014 at 5:51

Bhushan Kawadkar

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3 Comments

Seong Lee Over a year ago

Hi thanks, but this seems to make other radio buttons uncheck/check at the same time.

Bhushan Kawadkar Over a year ago

other radio button name attribute should be different, otherwise browser consider all of them under same radio button group and will allow you to check only single radio button i.e. whenever you select any radio button under same name then other will get deselected automatically.

Seong Lee Over a year ago

I have no radio group other than this. It does check/uncheck other radio buttons within the same group at the same time.

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