PHP code inside a javascript function

fatrandy13 · 03-11-2008, 02:55 PM

I have a PHP page: page.php

At some point in the file there is a javascript function.

Code:

function popAirType(){
     var db = document.forms[0].db.value;	
     AddToOptionList(document.forms[0].air_type, "","Select Airplane Type");

     <?php $query_string = "SELECT distinct air_type FROM my_table";

     $air_types = mysql_query($query_string);

     while ($air_types_row = mysql_fetch_array($air_types)){
          echo "AddToOptionList(document.forms[0].air_type, '" . $air_types_row['air_type'] ."', '" . $air_types_row['air_type'] . "');";
     }
     ?> 
}

Now, this code works great. i loop through the results of the query and (in php) echo out the appropriate javascript code to create the options in an html select box. No problems here.

What i'd like to do is add a WHERE clause to the query.

WHERE db_version = '(in here i want the javascript variable db)'

As you can see, I declare the variable "var db" at the first line of the function.

Is there anyway I can put the javascript variable inside the query I am running??

Guttorm · 03-11-2008, 03:11 PM

Hi

Remember PHP runs on the server and Javascript on the client. So you need to send the javascript variable as a parameter to the PHP script. For example:

Javascript:

Code:

window.location = 'page.php?db=' + db;

PHP:

Code:

$query_string = "SELECT distinct air_type FROM my_table WHERE db_version='".$_GET['db']."'";

Edit:
It's a bit complicated, but Javascript can also read XML data from a web-server. So you can send requests to the server with parameters and get back data as XML. You can get then it into variables in Javascript, and use it for e.g. setting the option lists of a select in a form. If you are interested, I suggest reading about Ajax.

derzok · 03-11-2008, 05:18 PM

AJAX is what you want. It will allow you to call php code from javascript (as long as the php code is in its own file). However, you must decide on an event that you want to trigger the php code with. For instance, when a user hovers their mouse over something or when they type something into a field. When you read up on AJAX all of this will make a bit more sense.

fatrandy13 · 03-12-2008, 10:36 AM

well, its all happening dynamiclly, so "GET" or "POST" data is out of the question.

there are multiple select boxes. values of these boxes are dynamicly generated based on the value of previous boxes...

so when i click the value of box 1, i want it to query the database with that value, then populate the next box with the results...

i have it working great execpt that i cant add the WHERE clause with javascript data, as described above

as for using AJAX, is there anything more concrete than "AJAX is what you want"...
what you described: "It will allow you to call php code from javascript".

i am already doing that in the code i posted..

thanks for the effort

karpi · 03-12-2008, 05:57 PM

Hello,

there is a framework for this.

Have a look at http://www.xajaxproject.org

They have an active community and some good examples.

HTH