Solved

counting checkboxes in javascript and passing to javascript function and php action

Posted on 2009-05-20
4
372 Views
Last Modified: 2012-05-07
I am building a form that lets the user check off a matrix of checkboxes, each which to indicate a location/category seleciton. I then want to pass the checked ones (location/category) to a javascript function to list and call PayPal, and then to a php script for subsequent entry into a database. The checkboxes arrays are created dynamically with php, as indicated in the sample code. Each has an onclick event that calls a funciton which increments a global counter if a box is checked, and decrements it if it is unchecked.

The questions are: 1) I am a bit confused on the syntax for calling the increment/decrement function - the array part is messing me up. 2) Once the user has checked all the boxes they want, I submit the form and call a javascript action where I need to get the various values of the checked checkboxes and fill in PayPal parameters and then some php code to fill in a database table with the purchased location/category. The AA, BB and CC indicate the name of a location in my database and the value 1, 2 and 3 indicates a id of a category record in the same database. These have to be sent to PayPal and then stored in the database.
... variou php code...

<input type=checkbox name=locA[] value=1 onclick=recalcTotal(this)>

<input type=checkbox name=locB[] value=1 onclick=recalcTotal(this)>

<input type=checkbox name=locC[] value=1 onclick=recalcTotal(this)>

<input type=checkbox name=locA[] value=2 onclick=recalcTotal(this)>

<input type=checkbox name=locB[] value=2 onclick=recalcTotal(this)>

<input type=checkbox name=locC[] value=2 onclick=recalcTotal(this)>

<input type=checkbox name=locA[] value=3 onclick=recalcTotal(this)>

<input type=checkbox name=locB[] value=3 onclick=recalcTotal(this)>

<input type=checkbox name=locC[] value=3 onclick=recalcTotal(this)>

...

<input type=checkbox name=locA[] value=n onclick=recalcTotal(this)>

<input type=checkbox name=locB[] value=n onclick=recalcTotal(this)>

<input type=checkbox name=locC[] value=n onclick=recalcTotal(this)>

...

more php code
 

javascript function recalctotal(obj) {

if obj.value=checked

   increment counter

else 

   decrement counter

}

Open in new window

0
Comment
Question by:Rich
  • 2
  • 2
4 Comments
 
LVL 12

Expert Comment

by:alien109
ID: 24434183
First suggestion - don't worry about tracking the clicks when a user selects the checkboxes. That will require to continually run the recalctotal function with logic to add/remove from what ever variable you were using to store the state.

Instead - just run the function on form submit.

If you enclose all of your checkbox elements in say a div tag, with an ID, you can easily access all of the checkboxes. Then when the form gets submitted, you run a function to calculate the total or whatever ever it is you need to do. See the snippets of HTML and JavaScript below (untested and for example only)


<script type="text/javascript">
function recalctotal() {
      var checksDiv = document.getElementById("checks");
      var checkList = checksDiv .getElementsByTagName("input");
      for(var i = 0; i < checkList.length; i++)
      {
            if(checkList[i].checked) {
                  // add to tally or whatever you need to do
            }
      }
}
</script>

<form ... onsubmit="recalctotal();">
      <div id="checks">
            <input type=checkbox name=locA[] value=3 />
            <input type=checkbox name=locB[] value=3 />
            <input type=checkbox name=locC[] value=3 />
      </div>
</form>
0
 

Author Comment

by:Rich
ID: 24435409
Well, as far as the first part, I need to keep a form field called TotalCost updated as each button is checked or unchecked. I add or subtract from TotalCost.value based on the checked == true or false of the button being checked.

The second part should work for what I am doing, however, and I will try that.
0
 
LVL 12

Accepted Solution

by:
alien109 earned 500 total points
ID: 24435511
OK, I think I understand why - I'm assuming it's to provide the user with live feedback of the totals.. Makes sense.

You can still use the script above, and call it on checkbox change.
0
 

Author Closing Comment

by:Rich
ID: 31583606
Thank you, that did the trick. So instead of passing only one value, I am passing the outer div element and waking through each checkbox.
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I imagine that there are some, like me, who require a way of getting currency exchange rates for implementation in web project from time to time, so I thought I would share a solution that I have developed for this purpose. It turns out that Yaho…
Password hashing is better than message digests or encryption, and you should be using it instead of message digests or encryption.  Find out why and how in this article, which supplements the original article on PHP Client Registration, Login, Logo…
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…
The viewer will learn how to dynamically set the form action using jQuery.

914 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

17 Experts available now in Live!

Get 1:1 Help Now