文章源自:http://viralpatel.net/blogs/listbox-select-all-move-left-right-up-down-javascript/

Listbox options javascript select all,move left-right, move up-down

While working with Listboxes I had to write few small JavaScript snippets to perform certain tasks like selecting all options / seselecting all options or moving options up and down or swapping the options between two listboxes. I thought of sharing the JavaScript functions with you so that you can bookmark the article and use the code whenever you need them.

Listbox Select All / Deselect All JavaScript

Following is the JavaScript function for implementing select all, deselect all options in listbox.

function listbox_selectall(listID, isSelect) {
        var listbox = document.getElementById(listID);
        for(var count=0; count < listbox.options.length; count++) {
            listbox.options[count].selected = isSelect;
    }
}

 The above javascript code is very straight forward. All you have to do it to pass the ID of listbox you need to perform select all/deselect all and a boolean value for select/deselect.
For example if a listbox has an id “countryList” following can be the function call.

listbox_selectall('countryList', true); //select all the options
listbox_selectall('countryList', false); //deselect all the options

 

Listbox Move up/down options JavaScript

Following is the javascript function that you can use to add move up/down options functionality. User can select any option and move it up in the list or down.

function listbox_move(listID, direction) {
 
    var listbox = document.getElementById(listID);
    var selIndex = listbox.selectedIndex;
 
    if(-1 == selIndex) {
        alert("Please select an option to move.");
        return;
    }
 
    var increment = -1;
    if(direction == 'up')
        increment = -1;
    else
        increment = 1;
 
    if((selIndex + increment) < 0 ||
        (selIndex + increment) > (listbox.options.length-1)) {
        return;
    }
 
    var selValue = listbox.options[selIndex].value;
    var selText = listbox.options[selIndex].text;
    listbox.options[selIndex].value = listbox.options[selIndex + increment].value
    listbox.options[selIndex].text = listbox.options[selIndex + increment].text
 
    listbox.options[selIndex + increment].value = selValue;
    listbox.options[selIndex + increment].text = selText;
 
    listbox.selectedIndex = selIndex + increment;
}

 Thus, you can call this function with first argument as list id and second argument a string value ‘up’ or ‘down’ depending on where you want to move the selected option.

listbox_move('countryList', 'up'); //move up the selected option
listbox_move('countryList', 'down'); //move down the selected option

 

Listbox swap/move left-right options JavaScript

Following is the javascript code for moving selected options from one listbox to another.

function listbox_moveacross(sourceID, destID) {
    var src = document.getElementById(sourceID);
    var dest = document.getElementById(destID);
 
    for(var count=0; count < src.options.length; count++) {
 
        if(src.options[count].selected == true) {
                var option = src.options[count];
 
                var newOption = document.createElement("option");
                newOption.value = option.value;
                newOption.text = option.text;
                newOption.selected = true;
                try {
                         dest.add(newOption, null); //Standard
                         src.remove(count, null);
                 }catch(error) {
                         dest.add(newOption); // IE only
                         src.remove(count);
                 }
                count--;
        }
    }
}

 Just call the function with two arguments, first is the source listbox id and second is the destination listbox id.

listbox_moveacross('countryList', 'selectedCountryList');