Getting checkbox value

gregd101 · 05-22-2012, 09:51 PM

I have a form with a few checkboxes

Code:

<input type='checkbox' name='idName[1]' checked><b> Data Cabinet - 7ft - 0113</td></tr>
<input type='checkbox' name='idName[2]' checked><b> Data Cabinet - 5ft -0463</td></tr>
<input type='checkbox' name='idName[3]' ><b> Data Cabinet - 5ft - 0463</td></tr>

I have a string with numbers of the name.
For instance the string "1,3"
Where I am trying to get the value of idName[1] and idName[3]

Code:

newTempArray =  s1.split(",");

for(var i=0; i<newTempArray.length; i++){
    k = newTempArray[i] ;
    m =  'idName[' + k + ']';
    tempElement = document.getElementsByTagName(m);
    document.write(tempElement);
    document.write(tempElement.getAttribute('checkbox') );
}

However I am getting an error on getting the elements value.
How can I get the elements checked status?

thanks

Old Pedant · 05-22-2012, 10:19 PM

getElementsByTagName means the name of the HTML tag. e.g, <a>, <br>, <span>. So you'd use getElementsByTagName("span") for example.

Code:

newTempArray =  s1.split(",");

var form = document.forms[0]; // or any other way to get to the <form> containing the checkboxes

for(var i=0; i<newTempArray.length; i++){
    k = newTempArray[i] ;
    var m =  'idName[' + k + ']';
    var cb = form[m];
    var cbvalue = cb.value;
    // but now you CAN NOT use document.write ... so what will you do?
}

If you use document.write once a page is complete, it WIPES OUT all content on the page, including even the javascript code that did the document.write!

Old Pedant · 05-22-2012, 10:24 PM

Generally, it's a bad idea to name the checkboxes as you did.

If you using PHP for your server-side code, you are better off using

Code:

<input type='checkbox' name='idName[]' checked><b> Data Cabinet - 7ft - 0113</td></tr>
<input type='checkbox' name='idName[]' checked><b> Data Cabinet - 5ft -0463</td></tr>
<input type='checkbox' name='idName[]' ><b> Data Cabinet - 5ft - 0463</td></tr>

If you are not using PHP, then better would be maybe

Code:

<input type='checkbox' name='idName_1' checked><b> Data Cabinet - 7ft - 0113</td></tr>
<input type='checkbox' name='idName_2' checked><b> Data Cabinet - 5ft -0463</td></tr>
<input type='checkbox' name='idName_3' ><b> Data Cabinet - 5ft - 0463</td></tr>

But there are exceptions, if you have a really good reason for the naming.

Maybe the best way, if using PHP, would be:

Code:

<input type='checkbox' id="cb1" name='idName[]' checked><b> Data Cabinet - 7ft - 0113</td></tr>
<input type='checkbox' id="cb1" name='idName[]' checked><b> Data Cabinet - 5ft -0463</td></tr>
<input type='checkbox' id="cb1" name='idName[]' ><b> Data Cabinet - 5ft - 0463</td></tr>

And then the JS code is simpler, too:

Code:

newTempArray =  s1.split(",");

for(var i=0; i<newTempArray.length; i++){
    var k = newTempArray[i] ;
    var cb = document.getElementById("cb" + k);
    var cbvalue = cb.value;
    // but now you CAN NOT use document.write ... so what will you do?
}

Old Pedant · 05-22-2012, 10:27 PM

LOL!!! I JUST NOTICED! You want to get the VALUES of those checkboxes...BUT NOT ONE OF THEM *HAS* a value!!!

Checkboxes *ONLY* have values if you assign them:

Code:

<input type="checkbox" name="whatever" value="THE VALUE GOES HERE"/>

They do have default values if you don't supply them, but the default is (I think) just "On", so is totally not useful.