Question

I am reposting this question with revised code that use more of jQuery.

Here is the HTML code that defines the objects:

<LEGEND><b>Select Study Sample</b></LEGEND>
<p>
<P CLASS=select_header>Study - Box - Well - Lab ID<br>
<SELECT multiple size=20 NAME="stylabid" ID="stylabid" onchange=show_stylabid() onclick=clear_fetch() STYLE="width: 115px">
<?php 
  $i=0;
  while ($i < $numstylabids) {
    $styarr = pg_fetch_row($stylabidresult);
    echo "<option value=$styarr[0]>$styarr[1]\n";
    $i++;           
  }
  ?>
</select>

and

<LEGEND><b>Select Project Sample</b></LEGEND>
<p>
<P CLASS=select_header>Project - Box - Well - Lab ID<br>
<SELECT multiple size=20 NAME="pjtlabid" ID="pjtlabid" onchange=show_pjtlabid() onclick=clear_fetch() STYLE="width: 115px">
<?php 
  $j=0;
  while ($j < $numpjtlabids) {
    $pjtarr = pg_fetch_row($pjtlabidresult);
    echo "<option value=$pjtarr[0]>$pjtarr[1]\n";
    $j++;           
  }
  ?>
</select>

Now, here is the javascript; I am simply trying to get the values of the selected object, which can be either a Study or a Project. I use this later to retrieve data from the database:

function fetchgenotype() {
    var ms, mndx, ss, sndex = 0;

    ms = $("#marker")[0].selectedIndex;    

    if (Study_selected) {
      ss = $("#stylabid")[0].selectedIndex;
      sndx = $("#stylabid").val(ss);
    } else
      ss = $("#pjtlabid")[0].selectedIndex;
      sndx = $("#pjtlabid").val(ss);
    }    

    // for debugging...    
 alert('ss='+ss+', sndx='+sndx);

This code dies on the line sndx = ... Would really appreciate any help!

TIA

Answer 1

Currently i don’t know what $(“#marker”) an Study_selected are.

Assuming there is anything OK so far, change the function into:

if (Study_selected) {
      sndx = $("#stylabid").val();
    } else
      sndx = $("#pjtlabid").val();
    }

val() returns the value of a form-element when used without an argument, otherwise it will set the value and return an jQuery-object.

There is no need to retrieve the selectedIndex, you may access the value of the select-element directly(it will be the value of the currently selected option)