changing order of elements in select menu

4 New Member

Hi,

I have constructed a clickable list of words which are added to a select box. I then have buttons to move the added elements up or down in the list.

The code below seems to work fine for the first change (UP only) but after that the last element in the list disappears :(

I have no idea why this is happening so could anyone offer a solution or a better method of doing the above task? Thanks in advance

Expand|Select|Wrap|Line Numbers

 <html>

<head>

<script type="text/javascript">
 
function moveText(name, id)

{

    var selected_box = document.getElementById("textarea_two");

    var new_option = new Option(name, id);

    selected_box.options[selected_box.length] = new_option;    

}
 
function moveup(){
 
    var y=document.getElementById("textarea_two").selectedIndex

    var x=document.getElementById("textarea_two").options
 
    if (y>0){

        var selected = x[y];

        var dest = x[y-1];
 
        //swap option elements

        x[y-1] = selected;

        x[y] = dest;    
 
        //reset variables if necessary ?

        x = null;

        y = null;

        selected = null;

        dest = null;    

    }

}

</script>

</head>
 
<body>

<table>

<tr>

<td id="textarea_one">

<li id= "1" title="text one" ondblclick="moveText(this.title, this.id)">text one</li>

<li id= "2" title="text two" ondblclick="moveText(this.title, this.id)">text two</li>

<li id= "3" title="text three" ondblclick="moveText(this.title, this.id)">text three</li>

</td>

</tr>

</table>
 
<br>

<select id="textarea_two" style="width:150px;" size="7"></select>

<br>
 
&nbsp;Move selected: <br>

><span onclick="moveup()">UP</span><br>

><span onclick="movedown()">DOWN</span>
 
</body>

</html>

Apr 25 '07 #1

Subscribe Reply

3039

technod

New Member

I've made a work around for this problem. I used a string to store both the previous and next values of each option element that is being changed so as to avoid loosing the data, which is what was happening in the above code.

Hope this might be useful to somebody. If anyone knows a simpler way of doing this please let me know! Cheers

Expand|Select|Wrap|Line Numbers

 <html>

<head>

<script type="text/javascript">
 
function moveText(name, id)

{

    var new_option = new Option(name, id);

    var x=document.getElementById("textarea_two").options;

    var y=document.getElementById("textarea_two").selectedIndex;

    new_option.tabIndex = x.length;

    //alert(new_option.tabIndex)

    var counter = 0

    //alert(new_option.text);

    //alert(x.length);
 
    //loop through option values if they exist and if the item has not already been added then add to list

    if (x.length > 0){

        for(var i=0;i<x.length;i++){    

        //alert(x[i].text)

            if (x[i].text == new_option.text){

                counter++;

            }

        }

        //alert(counter);

        if (counter == 0){

            x[x.length] = new_option;

        }else{

            alert("item already added to calendar!");

        }

    }else{

        x[x.length] = new_option;

    }
 
}
 
function reOrder(direction){
 
    //alert(direction);

    var y=document.getElementById("textarea_two").selectedIndex;

    var x=document.getElementById("textarea_two").options;
 
    var selected = x[y];
 
    //set the direction up or down

    if (direction == "up" ){

        var dest = x[y-1];

    }else if (direction == "down"){

        var dest = x[y+1];

    }
 
    var textString = dest.text;

    var valueString = dest.value;

    //alert(textString)
 
    //make string containing both values so that the 'dest' data is not lost in swap

    textString += "&"+selected.text;

    valueString += "&"+selected.value;

    //alert(textString)
 
    //first half equals destination text

    var firstHalfTextString = textString.substr(0,[textString.indexOf("&")]) 

    var firstHalfValueString = valueString.substr(0,[textString.indexOf("&")])

    //alert(firstHalfTextString)
 
    //second half equals selected text

    var secondHalfTextString = textString.substr(textString.indexOf("&")+1)

    var secondHalfValueString = valueString.substr(textString.indexOf("&")+1)

    //alert(secondHalfTextString)
 
    //swap the option elements text values

    selected.text = firstHalfTextString;

    dest.text = secondHalfTextString;

    selected.value = firstHalfValueString;

    dest.value = secondHalfValueString;
 
    //set the select to the moved element

    if (direction == "up" ){

        document.getElementById("textarea_two")[y-1].selected = true;

    }else if (direction == "down"){

        document.getElementById("textarea_two")[y+1].selected = true;    

    }

    //alert("tabindex="x.selected.tabIndex+"&value"+x.selected.value)****
 
}
 
</script>

</head>
 
<body>

<ul id="textarea_one">

<li id= "1" title="text one" ondblclick="moveText(this.title, this.id)">text one</li>

<li id= "2" title="text two" ondblclick="moveText(this.title, this.id)">text two</li>

<li id= "3" title="text three" ondblclick="moveText(this.title, this.id)">text three</li>

</ul>
 
<br>

<select id="textarea_two" style="width:150px;" size="7"></select>

<br>
 
&nbsp;Move selected: <br>

><span onclick="reOrder('up')">UP</span><br>

><span onclick="reOrder('down')">DOWN</span>
 
</body>

</html>

Apr 26 '07 #2

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