var subsecondClass = new Array();
var subthirdClass = new Array();
subsecondClass[0] = new Array('4','1','现代史')
subsecondClass[1] = new Array('3','1','近代史')
subthirdClass[0] = new Array('11','3','抗日战争')
subthirdClass[1] = new Array('12','3','甲午战争')
subsecondClass[2] = new Array('7','6','软件')
subthirdClass[2] = new Array('8','7','程序员')
subthirdClass[3] = new Array('10','7','web前端')
subsecondClass[3] = new Array('9','6','硬件')
subsecondClass[4] = new Array('5','2','小学教师资格')
function showSecondClass(selectValue)
{
document.getElementById('SmallClassID').length = 0;
document.getElementById('SmallClassID').options[0] = new Option('请选择','');
document.getElementById('ClassID').length = 0;
document.getElementById('ClassID').options[0] = new Option('请选择','');
for (var i=0; i<subsecondClass.length; i++)
{
 if (subsecondClass[i][1] == selectValue)
{
 document.getElementById('SmallClassID').options[document.getElementById('SmallClassID').length] = new Option(subsecondClass[i][2], subsecondClass[i][0]);
 }
 }
if (document.getElementById('SmallClassID').length>1) { document.getElementById('SmallClassID').style.display=''; }else{ document.getElementById('SmallClassID').style.display='none'; } }
function showThirdClass(selectValue)
{
document.getElementById('ClassID').length = 0;
document.getElementById('ClassID').options[0] = new Option('请选择','');
for (var i=0; i<subthirdClass.length; i++)
{
 if (subthirdClass[i][1] == selectValue)
  {
    document.getElementById('ClassID').options[document.getElementById('ClassID').length] = new Option(subthirdClass[i][2], subthirdClass[i][0]);
  }
 }
 if (document.getElementById('ClassID').length>1) { document.getElementById('ClassID').style.display=''; }else{ document.getElementById('ClassID').style.display='none'; }  }
document.write ("<select name='BigClassID' id='BigClassID' onChange='showSecondClass(this.value);'>");
document.write ("<option value='' selected>选择分类</option>");document.write ("<option value='1'>历史科目</option>");
document.write ("<option value='6'>计算机</option>");
document.write ("<option value='2'>教师资格证</option>");
document.write ("<option value='13'>英语</option>");
document.write ("</select>");
document.write (" <select name='SmallClassID' style='display:none;width:100px' id='SmallClassID' onChange='showThirdClass(this.value);'>");document.write ("<option value='' selected>请选择</option>");document.write ("</select>");
document.write (" <select name='ClassID' style='display:none;width:100px' id='ClassID'>");document.write ("<option value='' selected>请选择</option>");document.write ("</select>");