[RESOLVED] Forms, JS and PHP

shifty18

I am trying to make an order form. The order form allows people to choose the game, amount of slots, de-branding and rate, each of which effects the cost.
They want the users to have an amount on the fly, and this is easy with a piece of JS that adds up he values when anything is changed using onchange=AddUp()

The problem is my client wants it to be dynamic so they can add games, changes costs of debranding, rates etc.

What i need to happen is the user chooses a game, we will say MOHAA, this pulls from the DB the value of the field PPS which contains a number.

What i need to happen, is when the user selects $game it retrives $pps which is then used in the javascript

playerscost=(eval(document.forms.form.players.value)*</script> <?php echo $_GET['pps'];?><script>

this might be confusing but basically is it possible to retrive a value from a DB when the user selects a certain value from a drop downlist on the fly, or is this just not possible and will i need a form with an action to get all the infomation from the DB and then do the maths.

Hope you can understand
Thanks
Chris

Grisu

depending on the weight of your product-list you have different options. Javascript can not get a value from the db because it is only a browser-script. What you often see on the web is that people us a frame or an iframe. When you select the item, javascript will change the content of the iframe with the window.document.href-method calling a php-script like showvalue.php?partno=123 - this script can handle the database and update the value. This way you still need to load a small page when the user interacts, but not the heavy whole page.

The second method is completely Javascript-interactive, but the customer has to download the complete database-content each time he loads the page.
With PHP you create an Array in Javascript which contains all information about the product. In the select-field you have the
<option value="123">My Article</option>
and you can use your onChange.

Of help? Grisu

shifty18

ok so if i take your first option i would say have just an iframe in the content area of the page and this updates each time i choose an option but it only updates the iframe not the whole page

or if i use the second option, i download all of the table, place it into an array, and then in the JS call the bits of the array that i need

LoganK

Or you can use what I enthusiastically reccomend (look at my title below my username) - AJAX!!! AJAX, also known as "remote scripting", allows JavaScript to dynamically load files from a webserver, and then update the page through the DOM based on the result of the dynamically loaded files. Basically, JavaScript can query the webserver for any file, and the webserver returns the file, and then JavaScript can interact with the returned results. I'm not going to post an entire example here, because the method of constructing XMLHttpRequest() is a bit complex, but here's an example. Let's say that you want someone to be able to register. Your PHP file takes variables from $_POST, registers them in the DB, and echos either "true" or "false" (or "1" or "0", "success" or "fail", etc.). What JavaScript can do is "load" the results of processing that PHP file into it's own variable, and then you can have JS work with the page using the DOM, based on the result returned by PHP.

I hope this isn't too confusing. Here's some links to some very helpful tutorials. This technology really is useful for a variety of situations, and you can definitely use it for your problem.

http://developer.apple.com/internet/webcontent/xmlhttpreq.html

http://www.codingforums.com/archive/index.php/t-56788.html

http://borosenclave.com/%3Fp%3D154

http://www.webpasties.com/xmlHttpRequest/

http://smallinitiatives.com/2005/07/13/nice-ajax-tutorial/

shifty18

ok thanks alot, ill deffently take a look this afternoon

LoganK

You're welcome...post any other problems here, and if you need help specifically with AJAX, start a new thread in the appropriate forum and direct me to it.

shifty18

wow, it does look very powerful, but unfortunatly i have no knowlege of JS nor do I have enough to to complete this current probject and learn how to use this enogh to implament it for my needs, so I think I will need to think of another solution untill I can learn this new technology

Thanks for the pointer though, will be deffintly looked into in the near future

Chears
Chris

LoganK

Allright then. You're right - it is a very powerful technology, and avoids noticable page "refreshes" on things like yours.

Good luck doing it in PHP, and, as always, post here for help!