啥也不说了 直接上代码吧
<body>
<select id="qq" size="8" style="100px";>
<option >666</option>
<option >999</option>
</select>
<input type="button" id="c1" value="<<" />
<input type="button" id="c2" value=">>" />
<select id="wx"size="8" style ="100px">
<option>444</option>
<option>888</option>
</select>
</body>
</html>
<script>
var wx = document.getElementById("wx");
var cc = document.getElementById("cc");
var qq = document.getElementById("qq");
c2.onclick = function () {
var f = qq.selectedOptions[0];
var value =f.innerText
wx.appendChild(f);
}
c1.onclick = function () {
var x = wx.selectedOptions[0];
var value = x.innerText
qq.appendChild(x);
}