//设置单选下拉框选中
$("input:eq(0)").click(function () {
$("#single option").removeAttr("selected"); //移除属性selected
$("#single option:eq(1)").attr("selected", true); //设置属性selected
});
//设置多选下拉框选中
$("input:eq(1)").click(function () {
$("#multiple option").removeAttr("selected"); //移除属性selected
$("#multiple option:eq(2)").attr("selected", true); //设置属性selected
$("#multiple option:eq(3)").attr("selected", true); //设置属性selected
});
//设置单选框和多选框选中
$("input:eq(2)").click(function () {
$(":checkbox").removeAttr("checked"); //移除属性checked
$(":radio").removeAttr("checked"); //移除属性checked
$("[value=check2]:checkbox").attr("checked", true); //设置属性checked
$("[value=check3]:checkbox").attr("checked", true); //设置属性checked
$("[value=radio2]:radio").attr("checked", true); //设置属性checked
});