javascript selectæŽ§ä»¶é—´å† å®¹äº’ç›¸ç§»åŠ¨

<meta http-equiv="content-type" content="text/html; charset=iso-8859-1"> <title>insert title here</title> <table width="27%" height="194" border="0" cellpadding="1" cellspacing="0"><tr> <td width="21%"><select id="selectfrom" size="15" multiple style="width:100px"><option>a </option> <option>b </option> <option>c </option> <option>d </option> <option>e </option> <option>f </option> <option>g </option> <option>h </option> <option>i </option> <option>j </option> <option>k </option> <option>j </option> <option>m </option> <option>n </option></select></td> <td width="57%"> <p align="center"> <input name="addall" type="button" id="addall" value=" >> " style="width:40px" onclick="addall()"></p> <p align="center"> <input name="add" type="button" id="add" style="width:40px" value=" > " onclick="add()"></p> <p align="center"> <input name="del" type="button" id="del" value=" < " style="width:40px" onclick="del()"></p> <p align="center"> <input name="delall" type="button" id="delall" value=" << " style="width:40px" onclick="delall()"></p> </td> <td width="22%"><select id="select2" size="15" multiple style="width:100px"></select></td> </tr></table>
[ctrl+a 全选 注:如需引入外部js需刷新才能执行]