switch无效，总是执行 default：该怎么解决 _JavaScript

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>

------解决方案--------------------
语法错误：

switch (czs) {
case '3D':

break;
case '2B':

break;
default ：

break;
}
------解决方案--------------------
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';