Js function to change respecive cell value onchange selected value of dropdown value

[tarunkhatri]

Hi. I have a javascript function to change the value of the cell on chnage event of a dropdown list.My code is workin but the problem is that the value of the cell is chaning but not respective to the selected dropdown list( as there are 15 dropdown list and 15 cells), but only on the 1st cell. So need some identification for each cell. Can anyone help me just refine my code.

<script type="text/javascript"> 
function displaytaskid(ths) { 
    var id= ths.options[ths.selectedIndex].value;  
    alert (id);
    document.getElementById('task_id1').innerHTML=id;
} 
</script>

<?php for($count; $count <15; $count++)
{?>
 
    <tr>
        <td id ="task_id1[]"></td>
<td name = "task_id[]"><select name="task_id" id="dropdown" onchange="displaytaskid(this)">
    <option value=""></option>5
    <?php
 
      while($lp_row = pg_fetch_assoc($res2))
    {
          $val = $lp_row["task_id"];
          $caption = $lp_row["task_description"]; ?>
        <option value="<?php echo $val ?>"><?php echo $caption ?></option>
        <?php }  ?></select>
        </td>

[Dormilich]

of course you have to give out unique ids to get it working.

[tarunkhatri]

Yeahh Dormi I know tht. But I really dnt knw how to change my code to do that.

[Dormilich]

what about

echo "<td id=\"task_id_$count\">";

?

besides, you don’t even have to use ids, since the select and the td have the same parent.

[tarunkhatri]

THanks Dormi, sounds a good idea.. but then how to identify it by the js function(what change I need to do to my JS function) to identify each cell with the respective change in the dropdown list

[Dormilich]

how much do you know about DOM?

(you have 2 td per tr?)

[tarunkhatri]

yes there are 2 td per tr.. In one td there is the cell where i want my value to be changed and in 2nd is the actual dropdown list. which is trigerrin the js function. A little bit about DOM. Whenevery this JS bit comes in my code i get confused as I m really not good at it.

[Dormilich]

@tarunkhatri
time to get better… if you want to advance in JS, you need to know DOM. because DOM is what makes modifying HTML documents easy.

first some stuff to read:
DOM Intro (there are further articles listed)
DOM Intro @ W3C

some technical stuff
the DOM Specifications
the DOM IDL

[tarunkhatri]

Thanks vry much Dormi. This wud be really helpful. I know I really have to read this otherwise I ll keep on hanging around. But still rgt now if u have a solution for above do let me knw.

[Dormilich]

I have an idea.

parentNode.firstChild().nodeValue = this.value;

case closed*.

you need to know DOM to understand the meaning of that. and event listeners.


* – for me

[tarunkhatri]

Thanks for your effort.

[Dormilich]

and now for a working (FF) example

function setTD()
{
    this.parentNode.parentNode.firstElementChild.textContent = this.value;
}
// addEventForEach() is a custom function
document.getElementsByTagName("select").addEventForEach("change", setTD, false);

[tarunkhatri]

I have changed my code to below.. but still dosnt work.?? does any one has a solution

<script type="text/javascript"> 
function displaytaskid(ths,rowno) { 
    var id= ths.options[ths.selectedIndex].value;  
    alert (id);
   document.getElementById('task_id_rowno').innerHTML= id;
} 
 

<?php for($count; $count <15; $count++)
{?>
 
    <tr>
    <?php echo "<td id=\"task_id_$count\">"; ?>
    <?php
       $conn = connect();
     $res2 = sql_select1(); 
         ?>
 
    <td name = "task_id[]"><select name="task_id" id="dropdown" onchange="displaytaskid(this,\"$count\")">
    <option value=""></option>5
    <?php
 
      while($lp_row = pg_fetch_assoc($res2))
    {
          $val = $lp_row["task_id"];
          $caption = $lp_row["task_description"]; ?>
        <option value="<?php echo $val ?>"><?php echo $caption ?></option>
        <?php }  ?></select>
        </td>
 

[Dormilich]

JS, unlike PHP, does not search for variable names inside strings.

[tarunkhatri]

humm ok... I changed it to

 document.getElementById(rowno).innerHTML= id;

but still no result

[Dormilich]

if rowno is not the ID then you have no target element.

note: can you see, how useful the DOM is?

[tarunkhatri]

Thanks Dormi...I got a way around passinf count variable was doin all the prob..Anyways thanks very much for ur help