asked on

Referring to an HTML listbox (multiple select) using JavaScript

I have an HTML listbox in an ASP page in which users can select one or more values, as follows:

<select class='cInput' name="listbox" size=5 multiple STYLE='width:300px;'>

On submit a JavaScript function on the same page is called that referrences that listbox as follows:

lcValue =document.forms[formNo].listbox.options[document.forms[formNo].listbox.selectedIndex].value;

formNo is passed into the function.

If I use "var lcValue = String(trim(Request.Form("listbox")));" in another ASP page using POST and more than one value has been highlighted in the box then lcValue automatically returns a list seperated by commas.

However the JavaScript code "document.forms[formNo].listbox.options[document.forms[formNo].listbox.selectedIndex].value" only returns the first selected item in the listbox.

How can I get lcValue to return a comma seperated list in JavaScript?

Lord_McFly

Try the following (the last bit removes the trailing comma (,)...

var i
var lcValue

lcValue = ""

for(i=0; i<=document.forms[formNo].listbox.length - 1; i++)
      {
            lcValue = lcValue + document.forms[formNo].listbox.options[i].value + ","
      }


lcValue = lcValue.substr(0,lcValue.length - 1);

ASKER CERTIFIED SOLUTION

Bustarooms

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

kaiwhoeatspie

ASKER

Thanks, I will try your suggestions on Tuesday (weekend then national holiday in UK on Monday). Sorry that I can't test now.

kaiwhoeatspie

ASKER

I gave Bustarooms the points because:

a) code is cleaner, function can be reused
b) it only creates a comma seperated list for selected option values, not all of them

Bustarooms

ok, why the B?

kaiwhoeatspie

ASKER

Correct me if I am wrong but I think a B should be given for a question that has been answered correctly and to spec. An A is for a question that has been answered "beyond the call of duty", where extra special effort has been made beyond what was required.

Do you think that is not fair?

Bustarooms

to me, any help you get on this board, where someone takes the time to help you out is "beyond the call of duty"

Here's what EE thinks about grading
https://www.experts-exchange.com/help.jsp#hi73

kaiwhoeatspie

ASKER

I stand corrected. An "A" it is. I will contact EE and ask them to upgrade.