PHP - AJAX select with onchange event doesn't work

[hitman47]

Hallo.

 

I have a form

 

<form id="form2" method="post" action="insert_data.php>">

<select name="catid" id="catid" onChange="showkatigoria(this.value);">

<option  value="'. $row['catid'].'"><h4>' . $row['catname'].'</option> // something i need  with php, i dont' think it matters

<option  value="'. $row['catid'].'"><h4>' . $row['catname'].'</option>

<option  value="'. $row['catid'].'"><h4>' . $row['catname'].'</option>

//option value bla bla bla bla i have 4-5 options value.

</select>

 

My javascript:

 

 <script type="type/javascript">
        function showkatigoria(str)
        {
        if (str=="")
          {
          document.getElementById("catid").innerHTML="";
          return;
          }
        if (window.XMLHttpRequest)
          {// code for IE7+, Firefox, Chrome, Opera, Safari
          xmlhttp=new XMLHttpRequest();
          }
        else
          {// code for IE6, IE5
          xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
          }
        xmlhttp.onreadystatechange=function()
          {
          if (xmlhttp.readyState==4 && xmlhttp.status==200)
            {
            document.getElementById("catid").innerHTML=xmlhttp.responseText;
            }
          }
        xmlhttp.open("GET","insert_data.php?category="+str,true);
        xmlhttp.send();
        }
    </script>

 

 

It doesn't work what ever i do. Please help! I don't know javascript, let alone ajax.

 

It's urgent. Please help!

Edited October 24, 2013 by hitman47

[hitman47]

I want to mention that all my code is in one file.

 

In insert_data.php. Shall i use more? Shall i split the data?

 

I dont know ajax. Please help

[Ch0cu3r]

I would help if you explained what you're trying to do. 

[hitman47]

Its easy. I have a form with many select options. Like this website: http://www.tospitimou.gr/en/index.jsp

 

Check it at the top where it says YOU ARE AT. IF you choose an area then in the select box that follows some options are shown. If you choose something differnet in teh first select different choises come up in the second.

 

Same thing in this site: http://www.realestatecorner.gr/

 

I foy choose something in the "Περιοχή:"  that means location in greek, then a new select option emerges, that was not shown in the beggining. If you choose another location, other options come up. How shall i do iti? I dont have a clue about ajax. With the code i gave you

[Ch0cu3r]

Have a look at the following example to get an idea of how to do this

http://www.9lessons.info/2010/08/dynamic-dependent-select-box-using.html

http://www.satya-weblog.com/2007/04/dynamically-populate-select-list-by.html

[hitman47]

Thank you bro.

 

One question only. In the first link for example ajax sends the variable 'id' with post  to a different page than the original-mother select is. The mother select is in sections_demo.php and ajax sends the variable to ajax_city.php

 

From there it queries the dtabase and the extra option field is echoed. Why?

 

Could this be done within the same page sections_demo.php?

 

This is something i don't understand

Edited October 25, 2013 by hitman47

[Ch0cu3r]

From there it queries the dtabase and the extra option field is echoed. Why?

Because the output of the ajax request (ajax_city.php) is used to add the city options to the page for the selected country.

 

Could this be done within the same page sections_demo.php?

Yes. You just need to make sure when your php script receives the ajax request it only outputs the city options and not your whole webpage. For you to understand this more you'll want to research more about what is ajax and how it works.

Edited October 25, 2013 by Ch0cu3r