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Javascript: user adding items to a predefined dual select box

Posted on 2008-06-24
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Last Modified: 2008-07-03
I'm setting up a form for users to submit our papers/presentations to a database. One item is a list of authors. all papers will be authored by at least one and perhaps several of a predefined list of names (our employees). But some of them will include someone from outside our organizatIon, and I need to accommodate that possibility. So the user has to be able to add an arbitrary item to the list of authors. And ther ehave to be "Move up" and "Move down" buttons because the user isn't necessarily going to add then names in the correct order.

I've found some javascript that can do almost all that I want except for adding a name, at http://www.applicationgroup.com/tutorials/DualListBox/DualListBox_js.asp. I'm no javascript expert, but I can hack some code to support an "Add a Name" button. But I thought I'd ask to see if someone has such code lying around in the pile ...
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Question by:JonFleming
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3 Comments
 
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Accepted Solution

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GaryRasmussen earned 50 total points
ID: 21861640
here ya go ...

<html>
<head>
<script language="javascript">
function SwapItem(s, itemPos, swapPos)
{      var tempOption = new Array(s.options[swapPos].text, s.options[swapPos].value);
    s.options[swapPos].text = s.options[itemPos].text;
    s.options[swapPos].value = s.options[itemPos].value;
    s.options[itemPos].text = tempOption[0];
    s.options[itemPos].value = tempOption[1];
    s.selectedIndex = swapPos;
}

function MoveUp()
{      var list = document.getElementById("cboAuthors")
      if (list.selectedIndex != -1 && list.selectedIndex != 0)
      {      SwapItem(list, list.selectedIndex, list.selectedIndex - 1)
      }
}

function MoveDown()
{      var list = document.getElementById("cboAuthors")
      if (list.selectedIndex != -1 && list.selectedIndex != (list.length -1))
      {      SwapItem(list, list.selectedIndex, list.selectedIndex + 1)
      }
}

function Add()
{      var list = document.getElementById("cboAuthors")
      var newAuthor = document.getElementById("txtNewAuthor").value
      
      var option = new Option(newAuthor, newAuthor)
    list.options[list.options.length] = option
}

function Remove()
{      var list = document.getElementById("cboAuthors")
      if (list.selectedIndex != -1)
      {      list.options[list.selectedIndex] = null
      }
}

</script>
</head>
<body>
<form>
<select id="cboAuthors" size="10" name="cboAuthors">
<option value="Dog">Dog</option>
<option value="Cat">Cat</option>
<option value="Horse">Horse</option>
<option value="Fish">Fish</option>
</select>

<br><br>

<input type="button" value="Move Up" onclick="MoveUp()">
<input type="button" value="Move Down" onclick="MoveDown()">
<input type="button" value="Remove" onclick="Remove()">

<br><br>

New Author:<input type="text" id="txtNewAuthor"><input type="button" value="Add" onclick="Add()">

</form>
</body>
</html>
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LVL 1

Expert Comment

by:GaryRasmussen
ID: 21861653
Updated the Add function to make sure there is actually something to add

function Add()
{      var list = document.getElementById("cboAuthors")
      var newAuthor = document.getElementById("txtNewAuthor").value
      
      if (newAuthor != "")
      {      var option = new Option(newAuthor, newAuthor)
            list.options[list.options.length] = option
      }
}
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Author Comment

by:JonFleming
ID: 21864301
Ah, thank you.
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