JavaScript & PHP checkbox select all

Question

I have problem with select checkbox with the JavaScript in the HTML file. I know how to do this but in my form all checkbox have name='chk[]':

<form name="forms" action='index.php' method='post'>
    <input type='checkbox' name='chk[]' value='value1'> ANY VALUE 1 </br>
    <input type='checkbox' name='chk[]' value='value2'> ANY VALUE 2 </br>
    <input type='checkbox' name='chk[]' value='value3'> ANY VALUE 3 </br>
    <input type='checkbox' name='chk[]' value='value4'> ANY VALUE 4 </br>
    <input type='submit' name='submit' value='Get Value'>
</form>

In my PHP file I use select checkbox:

<?php
    $s = "";
    $value = $_POST['chk'];

    $s .= join(", ", $value);

    echo $s;

But how can I create a function in JavaScript which checks the field. I've also tried this

Include the HTML for the checkboxes that is generated by your PHP code in the question, as well as the Javascript code you've tried that doesn't work, please. — Anthony Grist, Feb 21 '12 at 16:51
So you want a script that checks all the checkboxes? Would it make sense to do this when the form is rendered, or is this a convenience button for the user to one-click and check all the boxes? — Surreal Dreams, Feb 21 '12 at 16:56

Dennis · Accepted Answer · 2012-02-21T17:13:44.880

2

To check all checkboxes dynamically, you can use the follwing code:

var inputs = document.getElementsByTagName("input");
for(var i = 0; i < inputs.length; i++)
    if(inputs[i].type == "checkbox")
        inputs[i].checked = true;

To check a checkbox by default, just add checked='checked' to the tag:

<input type='checkbox' name='chk[]' value='value' checked='checked'>

edited Feb 21 '12 at 17:13

answered Feb 21 '12 at 17:06

Dennis

14,264
2
48
57

1

Replace `'checked'` with `true`. You are accessing the boolean property, not the string attribute. – ThiefMaster Feb 21 '12 at 17:10
Ok thx it's work fine now. I must create dynamic check, uncheck checbox in site generate by php. I don't know hove much was checkbox, and I need take it value. – quba88 Feb 21 '12 at 21:41

JavaScript & PHP checkbox select all

1 Answers1