Although it is a simple effect, it still needs to be accumulated and recorded;
The source code is as follows:
<select id="myselect1"> <option value="">― ―</option> <option value="2015">2015</option> <option value="2014">2014</option> <option value="2013">2013</option> <option value="2012">2012</option></select><br><br><select id="myselect2"> <option value="">― ―</option> <option value="2015">2015</option> <option value="2014">2014</option> <option value="2014">2014</option> <option value="2014">2014</option> <option value="2013">2013</option> <option value="2012">2012</option></select> var time = new Date(); var month=time.getMonth()+1; var day=time.getDay(); if(month>5&&day>1){ var objSelect=document.getElementById("myselect2"); objSelect.options.add(new Option("2016", "2016"),1); objSelect.options.remove(5); } if(month>7&&day>1){ var objSelect=document.getElementById("myselect1"); objSelect.options.add(new Option("2016 level", "2016 level"),1); objSelect.options.remove(5); }