switch无效，总是执行 default：
出发chkcz（）函数的是select菜单中的onchange()，现在存在的错误是，switch无效，总是执行 default：结果

HTML code

   <select name="btype" id="btype" onchange="chkcz()">        <option selected="selected">请选择</option>        <option value="3D">3D</option>        <option value="2B">2B</option>        <option value="367">367</option>        <option value="265">265</option>      </select>

JScript code

function chkcz(){       var czs=document.form1.btype.value;switch (czs) {    case '3D':        document.form1.award12.value='1000';        document.form1.award22.value='';        document.form1.award32.value='';        document.form1.award42.value='';        document.form1.award52.value='';        document.form1.award62.value='';        document.form1.award72.value='';    case '2B':        document.form1.award12.value='5,000,000';        document.form1.award22.value='';        document.form1.award32.value='3000';        document.form1.award42.value='200';        document.form1.award52.value='10';        document.form1.award62.value='5';        document.form1.award72.value='';    case '367':        document.form1.award12.value='';        document.form1.award22.value='';        document.form1.award32.value='';        document.form1.award42.value='500';        document.form1.award52.value='100';        document.form1.award62.value='10';        document.form1.award72.value='46';    case '265':        document.form1.award12.value='';        document.form1.award22.value='50';        document.form1.award32.value='';        document.form1.award42.value='';        document.form1.award52.value='';        document.form1.award62.value='';        document.form1.award72.value='';    default:        document.form1.award12.value='';        document.form1.award22.value='';        document.form1.award32.value='';        document.form1.award42.value='';        document.form1.award52.value='';        document.form1.award62.value='';        document.form1.award72.value='';    }}</script>

[解决办法]
语法错误：

switch (czs) {
case '3D':

break;
case '2B':

break;
default ：

break;
}
[解决办法]
switch (czs) {
case '3D':
document.form1.award12.value='1000';
document.form1.award22.value='';
document.form1.award32.value='';
document.form1.award42.value='';
document.form1.award52.value='';
document.form1.award62.value='';
document.form1.award72.value='';
break；
case '2B':
document.form1.award12.value='5,000,000';
document.form1.award22.value='';
document.form1.award32.value='3000';
document.form1.award42.value='200';
document.form1.award52.value='10';
document.form1.award62.value='5';
document.form1.award72.value='';
break；
case '367':
document.form1.award12.value='';
document.form1.award22.value='';
document.form1.award32.value='';
document.form1.award42.value='500';
document.form1.award52.value='100';
document.form1.award62.value='10';
document.form1.award72.value='46';
break；
case '265':
document.form1.award12.value='';
document.form1.award22.value='50';

document.form1.award32.value='';
document.form1.award42.value='';
document.form1.award52.value='';
document.form1.award62.value='';
document.form1.award72.value='';
break；
default:
document.form1.award12.value='';
document.form1.award22.value='';
document.form1.award32.value='';
document.form1.award42.value='';
document.form1.award52.value='';
document.form1.award62.value='';
document.form1.award72.value='';
break；
不加break；将匹配的case 开始执行，直到default，所以最后的结果是：
document.form1.award12.value='';
document.form1.award22.value='';
document.form1.award32.value='';
document.form1.award42.value='';
document.form1.award52.value='';
document.form1.award62.value='';
document.form1.award72.value='';
[解决办法]
var czs=document.form1.btype.value;下拉菜单取值错误，所以没有对应值 就一直defalut

var obj=document.getElementById("btype");
var czs=obj.options[obj.selectedIndex].text;//用这两句取值