selectedIndex value of the last selected item in select box

[samvb]

I need to know how to get id of the last selected item in a multiple list box using javascript. It keeps on givin me 0 or 1...any tips would be great. Note i wanna store it in a variable and that variable should store id of the last selected item.

[philipwayne]

I haven't done much with forms in JavaScript but I'd imagine you could do this with something like

var x = selected.item( selected.length - 1 ).id
 

[RamananKalirajan]

@samvb,
Can you please share the code what you have done?

Thanks and Regards
Ramanan Kalirajan

[samvb]

function SelectedItems(selectBoxName,maxallowed) {
    //used to know how many items selected in <select box>
 
    var obj=document.getElementById(selectBoxName);
    var lastclicked=obj.selectedIndex;
 
    var btnobj=document.getElementById(submitbutton);//submit or upload or so button.
  var numberSelected=0
 
  for (var i=0; i < obj.options.length; i++) {
     if (obj.options[i].selected == true){
       numberSelected++;
     }//end if
        }//end loop
 
 
 if (numberSelected>maxallowed){
     alert("You can't select " + maxallowed + " items. Please deselect at least one item to proceed.");
     btnobj.disabled=true;
 
     obj.options[lastIndex].selected=false;
 return;
 }//end if
 else{
 
 }//end else
}//end function

Now i wanted to store id of the last clicked item in lastindex variable.

[RamananKalirajan]

Hi samvb,
I was not able to understand you requirement clearly. I just gone through your code. From that I can understand that you are having a multiple select element. You can select so many options. Whether you want to find which option was selected finally?

Thanks and Regards
Ramanan Kalirajan

[samvb]

@RamananKalirajan

When the user selects, say 3 which is the maximum allowed, i need to warn him about it and deselect the last item selected.

[philipwayne]

I misunderstood your post.

<script type="text/javascript">
    var lastIndex = false;
    function validate( select )
    {
        var max = 3;
        var x;
        var count = 0;
        for( x = 0; x < select.options.length; x++ )
        {
            if( select.options[x].selected == true )
                count++;
        }
        if( count > max )
        {
            alert( "To many items selected!" );
            select.options[lastIndex].selected = false;
        }
    }
</script>
<select id="myselect" onchange="validate( this );" multiple="multiple">
    <option onmousedown="lastIndex = this.index">1</option>
    <option onmousedown="lastIndex = this.index">2</option>
    <option onmousedown="lastIndex = this.index">3</option>
    <option onmousedown="lastIndex = this.index">4</option>
    <option onmousedown="lastIndex = this.index">5</option>
    <option onmousedown="lastIndex = this.index">6</option>
    <option onmousedown="lastIndex = this.index">7</option>
</select>
 

Also do note we must use the onmousedown function not onclick or onmouseup onchange will happen before onclick and onmouseup in term making the function deslected the wrong option.