javascript refresh a select box without refreshing page

[cleary1981]

Hi, I am trying to improve the usabilty of an app I have written and it would be great if I could refresh the content of my select boxes without refreshing the whole page.

I am sure this could be done. perhaps using iFrames. Can anyone shed some light?

[RamananKalirajan]

Refreshing the Select Box withut refreshing the page means in what way you want to refresh the select box. Wether are u adding the Database values into that select box or user defined values in that page should be added to the select box.

Regards
Ramanan Kalirajan

[cleary1981]

the select box is populated from my database. when I add a new item to my database i want to see the values in the select box without refreshing.

[gits]

so you want to push an update to a webapp when your database changes without user interaction? you just need to use an ajax-call and poll the db with it ... you have to decide how often you need that and you may use setInterval() for this purpose ... you just cannot really push things to the client ... the client has to request the update ...

kind regards

[cleary1981]

Yeah i have the function of adding to my database on the same page so when I add a new item to my database I want the selectbox which is a list of records to now contain the new one. Can you show me how this is done with ajax?

[gits]

that is not nessecary then ... you could add the option to the DB with the call and besides that you just need to add it to the node with dom-methods to avoid requests/traffic ... what have you done so far?

[cleary1981]

Its is neccessary because I have three select boxes linked together. I need to turn my requests into ajax requests. Thanks for your help anyway. Below are the unctions I am currently using to populate my select boxes

<?php
 
require "config.php"; // database connection details 
echo "
 
function fillType(){
    //this function is used to fill the companies in main.php on load
";    
 
$q11=mysql_query("SELECT type FROM module_type");
echo mysql_error();
while($nt11=mysql_fetch_array($q11)){
echo "addOption(document.form1.newtype, '$nt11[type]', '$nt11[type]');";}// end of while
?>
}
 
function fillType2() {
 
removeAllOptions(document.form1.selecttype);
addOption(document.form1.selecttype, "", "Select", "");
<?php    
$q77=mysql_query("SELECT type FROM module_type");
echo mysql_error();
while($nt77=mysql_fetch_array($q77)){
echo "addOption(document.form1.selecttype, '$nt77[type]', '$nt77[type]');";}// end of while
?>
}
 
function fillNewSub() {
    removeAllOptions(document.form1.newsub);
    addOption(document.form1.newsub, "", "Select", "");
 
    <?php
        $q22=mysql_query("select distinct(type) from subtype"); 
        while($nt22=mysql_fetch_array($q22)){
            echo "if(document.form1.newtype.value == '$nt22[type]'){";
            $q32=mysql_query("select subtype from subtype where type='$nt22[type]' order by subtype asc");
            while($nt32=mysql_fetch_array($q32)){
            echo "addOption(document.form1.newsub,'$nt32[subtype]', '$nt32[subtype]');";
 
            } // end of while loop
            echo "}"; // end of JS if condition
        }
?>
}
 
function fillselectsub(){
    removeAllOptions(document.form1.selectsub);
    addOption(document.form1.selectsub, "", "Select", "");
 
    <?php
        $q55=mysql_query("select distinct(type) from subtype"); 
        while($nt55=mysql_fetch_array($q55)){
            echo "if(document.form1.selecttype.value == '$nt55[type]'){";
            $q56=mysql_query("select subtype from subtype where type='$nt55[type]' order by subtype asc");
            while($nt56=mysql_fetch_array($q56)){
            echo "addOption(document.form1.selectsub,'$nt56[subtype]', '$nt56[subtype]');";
 
            } // end of while loop
            echo "}"; // end of JS if condition
        }
?>
}
 
function fillselectmod(){
    removeAllOptions(document.form1.selectmod);
    addOption(document.form1.selectmod, "", "Select", "");
 
    <?php
        $q44=mysql_query("select distinct(subtype) from module"); 
        while($nt44=mysql_fetch_array($q44)){
            echo "if(document.form1.selectsub.value == '$nt44[subtype]'){";
            $q45=mysql_query("select module_name from module where subtype='$nt44[subtype]' order by module_name asc");
            while($nt45=mysql_fetch_array($q45)){
            echo "addOption(document.form1.selectmod,'$nt45[module_name]', '$nt45[module_name]');";
 
            } // end of while loop
            echo "}"; // end of JS if condition
        }
?>
}
 
 
function removeAllOptions(selectbox)
{
    var i;
    for(i=selectbox.options.length-1;i>=0;i--)
    {
        //selectbox.options.remove(i);
        selectbox.remove(i);
    }
}
 
function addOption(selectbox, value, text )
{
    var optn = document.createElement("OPTION");
    optn.text = text;
    optn.value = value;
 
    selectbox.options.add(optn);
}
 

[gits]

so you mean you have to update all three select-nodes when adding a new option to one of them? as i said ... then you need something that does the following steps:

1. user adds an option
2. start your ajax-call and insert the option to the db
3. when inserted retrieve the data from the db
4. send back the result
5. the onreadystatechange-handler could now update the list-nodes

[cleary1981]

ok heres what I have for the first select. I can get the values into my program but how do I put the values into the select?

function ajax_filltype(){
    var x=0;
    var url = "filltype.php?x=" + escape(x);
    url = url + "&dummy=" + new Date().getTime();
    request.open("GET", url, true);
    request.onreadystatechange = populateselecttype;
    request.send(null); 
}
function populateselecttype() {
    if (request.readyState == 4) {
        var response = request.responseText;
        var splitResult = response.split("%%");
        for (i=0; i<splitResult.length-1; i++){
            alert(splitResult[i]);
            //add each option i to select box
        }
    }
 
}

php

<?php
 
require "config.php";
 
$q1=mysql_query("SELECT type FROM module_type");
while($r = mysql_fetch_array($q1)){
        echo $r['type'] . '%%';
 
  }
?>

[cleary1981]

never mind it was just

function populateselecttype() {
    if (request.readyState == 4) {
        var response = request.responseText;
        var splitResult = response.split("%%");
        for (i=0; i<splitResult.length-1; i++){
            document.form1.selecttype.options[document.form1.selecttype.length] = new Option(splitResult[i], splitResult[i]);
        }
    }
 
}