[End User]

I have a form that lets people copy items from one select list to another, but I want to prevent them from putting duplicate items into the second list. In other words, they can pick as many items from the first list as they want, but they can't pick and add the same one twice.

In the code below, what would be the best way to prevent adding duplicate items to the "destList.options" array?

// Populate  destination with  items from new array
for ( var j = 0; j < newDestList.length; j++ ){

    if ( newDestList[ j ] != null ){

	      destList.options[ j ] = newDestList[ j ];

    }

}

[TwoD]

Why not remove the item from the first list as they are added to the second?

[End User]

Originally Posted by TwoD

Why not remove the item from the first list as they are added to the second?

My bad, I should have explained this in the original post. In this particular case I need to leave all of the elements in the original array.

[End User]

I have this mostly sorted, but I'm now trying to figure out how to add an 'onclick()' event to a dynamically created element:

var y=document.createElement('option');
y.value=tmp1;
y.text=tmp;
y.onclick = moveinid();

I've tried numerous variations on the line in bold, using setAttribute, attachEvent, etc etc and still haven't hit on it. How does one attach an onclick event in this circumstance?

[TwoD]

Remove the parenthesis. You're calling the function and assigning its return value to onclick, instead of assigning it the function reference itself.

[End User]

Originally Posted by TwoD

Remove the parenthesis. You're calling the function and assigning its return value to onclick, instead of assigning it the function reference itself.

Actually, I tried that earlier but couldn't get that to work either. I also tried 'addListener', and a couple of other variations with no luck.

[wirehopper]

<script type="text/javascript">
document.write('<span id="test">Test</span>');
t=document.getElementById('test');
t.setAttribute('onclick',bork);  /* Set onclick attribute */
function bork(e)
{
alert('Bork');
}
</script>

As far as the duplicate issue - options:

Create an array that lists the items in the first select statement, as well as a flag to indicate whether the user selected them. If the user already selected the item, disregard reselections.

-- or --

Use the sort JavaScript sort() Method to sort the target array. That should make the search process quicker.

-- or --

Flatten the target array with JavaScript join() Method and search the resultant string.

[End User]

<script type="text/javascript">
document.write('<span id="test">Test</span>');
t=document.getElementById('test');
t.setAttribute('onclick',bork);  /* Set onclick attribute */
function bork(e)
{
alert('Bork');
}
</script>

Hmmmm, I tried the code above a couple of ways but couldn't get it to work. I think it may be due to the fact that I'm dynamically building the list via javascript, but I really don't know yet.

On the dupe-prevention, I did resort to just searching the list each time and rejecting the element addition if it was already there.

Finally (or maybe not, lol) I swear that IE is the most retarded browser in the Universe. Now, maybe there's another Universe where IE is not the most retarded browser, but that remains to be seen. I say this for one simple reason:

IE just doesn't support event handlers from the option element. In other words, this code here won't work:

<form>
<select>
<option onclick="doSomething()">Option Number 1</option.
</select>
</form>

It'll work in every browser that I know of except IE. The onclick only works in IE when it's used on the <select> tag. Yeah, there are workarounds to handle both cases, but I'm so sick of having to code extra junk for IE that I want to vomit. IE simply does not follow the HTML specifications:

Forms in HTML documents
http://www.w3.org/TR/html401/interact/forms.html#h-17.6

It says right there that the <OPTION> part of the <SELECT> element has an onclick event handler available. Not "maybe", not "optionally", not "if Microsoft feels like it", the spec says it will contain this event as an intrinsic property.

[wirehopper]

You might want to use onchange/onclick on the select.