jquery如何让select选中某个选项的实例详解

<span id="xx">广州市</span>
<select id="select_id"> 
<option>北京市</option> 
<option>广州市</option> 
<option>上海市</option>
</select>

$("#select_id option[text='广州市']").attr("selected", true); 
<script>
//普通js写法
document.getElementById("select_id").options[1].setAttribute("selected", true);
//jquery应该这样写
$("#select_id option").eq(1).attr("selected",true);
</script>
<script>
 $("#select_id option[value='广州市']").attr("selected", true);
</script>
$("#select_id option[text='广州市']").attr("selected", "selected");

 $("#select_id")[0].selectedIndex = 1;

$('#selectId').get(0).selectedIndex=index;

$('#selectId').val('selectIndexValue');

$("#select_id").val();

$("#select_id").find("option:selected").text();