linked comboboxes in html

Basically my webpage has two comboboxes. First combo box is populated with data comming from MySql. There is a button Add to the side of combo box and when user selectes a item in combo box 1 , clicks on the Add button, that item should get added to the second combo box tha开发者_开发技巧t is in the same page. Can anyone please tell me how to do this in javascript? or anything?

By the way my web pages are PHP pages.

Thanks.

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Hey. You could use a Javascript function like this:

function moveSelectedOption() {
    // Fetch references to the <select> elements.
    var origin = document.getElementById('origin_select');
    var target = document.getElementById('target_select');

    // Fetch the selected option and clone it.
    var option = origin.options[origin.selectedIndex];
    var copy = option.cloneNode(true);

    // Add the clone to the target element.
    target.add(copy, null);
}

Then you just add a call to it to the button's onclick event.

<button onclick="moveSelectedOption()">Add</button>

If you want to move it rather than copy it, remove the cloneNode line and just add the original option.