js设置下拉框选中后change事件无效解决

<select id="bigType">
     <option value="">请选择</option>
     <option value="1">xiamen</option>
     <option value="2">beijing</option>
</select>

<select id="smallType">
     <option value="">请选择</option>
</select>

jQuery("#bigType").change(function(){
    //do something
});

jQuery("#bigType option[value="1"]").attr("selected","selected")
//jQuery("#bigType option:contains("xiamen")").attr("selected","selected")

<select id="bigType" onChange="getVariety(this.options[this.selectedIndex].value)">
     <option value="">请选择</option>
</select>

function getVariety(val){
     //set some options checked
}