随机选择器

Posted 2021-02-25

window.onload = function(){
  document.getElementById("randomButton").addEventListener('click', selectRandomOption, false);
}
 
function selectRandomOption() { 
  var box = document.getElementById('s_box');
  box.selectedIndex=box.length-1;
  box.selectedIndex=((Math.random()*box.length)-1);
};