select实现多选

XHTML CSS JAVASCRIPT XML PHP C# JAVASCRIPT XML PHP C# JAVASCRIPT XML PHP C# JAVASCRIPT XML PHP C# JAVA C++ PERL

<script language="javascript">
   function show(){
  var sel = document.forms["form1"].s1;
  var s = "";
  for(var i=0;i<sel.options.length;i++){
     if(sel.options[i].selected) s += sel.options[i].innerText + ",";
  }
  if(s!="") s = s.substr(0,s.length-1);
  alert(s);
     }
</script>

转自：http://www.okajax.com/a/201106/select.html