【www.gdgbn.com--js教程】

js 检测 select多选项个数

<script type="text/javascript教程">

function howMany (selectItem) {
  var numberSelected=0

  for (var i=0; i < selectItem.options.length; i++) {
     if (selectItem.options[i].selected == true)
       numberSelected++;
  }

  return numberSelected
}

</script>


Choose some book types, then click the button below:



onclick="alert ("Number of options selected: " + howMany(document.selectForm.bookTypes))">

本文来源：http://www.gdgbn.com/wangyezhizuo/23646/