Looping through a checkbox array that has one element

Question

I have a list of dynamically created checkboxes named "tags" which I loop through with javascript to make sure only 1 is checked and to get the value. If for some reason this list of checkboxes only has 1 item, my script won't look at it. When I alert the tag's length I get undefined.

    var total=[];
    for (var i=0; i < document.form1.tags.length; i++){
        if(document.form1.tags[i].checked==true){
            total.push(document.form1.tags[i].value);
        }
    }

    if(total.length==0){
        alert("Please select a product to edit.");
    }else if (total.length>1){
        alert("Please select only one product to edit.");
    }else{
        document.location = "go somewhere";
    }

.tags is not an array when there is only one checkbox, it contains direct reference to the one checkbox. It only becomes a nodelist when there are more than one checkboxes with the same name. You should always look at the developer console and you would have seen the error there. — Esailija
– Esailija, Commented Nov 8, 2012 at 22:14
@Esailija Yet another reason to use querySelectorAll or jQuery. — John Dvorak
– John Dvorak, Commented Nov 8, 2012 at 22:16

nirazul · Accepted Answer · 2012-11-08 22:19:11Z

4

Why do you need Checkboxes? Wouldn't this be a great opportunity to use Radiobuttons?

answered Nov 8, 2012 at 22:19

nirazul

3,9654 gold badges30 silver badges49 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Eli Gassert · Accepted Answer · 2012-11-08 22:18:42Z

2

Two suggestions:

use getElementsByName instead to get all the elements so you can iterate them:
Use a framework like jquery. Any reason you can't use jquery or another framework? Your life would be so much easier.

var tags = document.getElementsByName('tags');
for(var i = 0; i < tags.length; ++i)
{
    if(tags[i].checked) .....
}

answered Nov 8, 2012 at 22:18

Eli Gassert

9,7713 gold badges33 silver badges40 bronze badges

Comments

Kevin Boucher · Accepted Answer · 2012-11-08 22:36:29Z

2

You want radio buttons.

<input type='radio' name='tags' value='[whatever]' />

You won't have to 'check and make sure only one is selected'. And to get the

var tags = document.getElementsByName('tags'),
    value = '', i = 0;

for( ; i < tags.length; i++ )
{
    if( tags[i].checked ) {
        value = tags[i].value;
        break;
    }
}

answered Nov 8, 2012 at 22:36

Kevin Boucher

16.8k3 gold badges51 silver badges57 bronze badges

1 Comment

Kenro Over a year ago

Can't use radio buttons. Depending on what button is pressed multiple selections is allowed.

bas · Accepted Answer · 2012-11-08 22:16:25Z

-1

from the top of my head... if there is only one checkbox selected it might be document.form1.tags is not an array...

answered Nov 8, 2012 at 22:16

bas

6281 gold badge9 silver badges23 bronze badges

Collectives™ on Stack Overflow

Looping through a checkbox array that has one element

4 Answers 4

Comments

Comments

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related