Execute query on button click If checkbox is checked - php

Question

I want to execute a script if checkbox is checked when I click on the submit button.
I got the following code snippet in my overview.php:
<table style="width: 100%; font-size: 11;">
<tr>
<td colspan="6">
<form method="post" action="update.php" target="_blank">
<script language="JavaScript">
function toggle(source) {
checkboxes = document.querySelectorAll("input[name^='box[']");
for(var i=0, n=checkboxes.length;i<n;i++) {
checkboxes[i].checked = source.checked;
}
}
</script>
<input type="submit" name="update" value="Update - LoL / BoL">
<input type="checkbox" onClick="toggle(this)" name="All" value="All"> Select all
</form>
</td>
</tr>
<tr>
<th>ve067</th>
<th>ve378</th>
<th>ve724</th>
<th>ve725</th>
<th>ve726</th>
<th>ve727</th>
</tr>
<tr>
<td>
<form method="post" action="update.php">
<input type="checkbox" name="box[1]" value="ve067_LB1"> LeagueBot 1<br>
<input type="checkbox" name="box[2]" value="ve067_LB2"> LeagueBot 2<br>
<input type="checkbox" name="box[3]" value="ve067_LB3"> LeagueBot 3<br>
<input type="checkbox" name="box[4]" value="ve067_LB4"> LeagueBot 4<br>
</form>
</td>
</tr>
</table>
And this is a code snippet from my update.php:
<?php
if(isset($_POST['update'] && $_POST['box[4]']) {
// code here
}
?>
But it does not work for me.

Answer 1

You can do it as I have mentioned in a post on pastebin
Hope it helps you dude.

Answer 2

Solution: Consider the following JSFiddle
Explanation: This will validate to see that at least checkbox 'box[4]' has been ticked.
The "key" code here being the return function in the following line.
<input type="submit" name="update" value="Update - LoL / BoL" onclick="return validate();">
Update: Made to accommodate extra information given in comment.
Remember: The validation here is done on the client side so that it doesn't need to query the server (PHP) first