您可以使用:first selector:
var firstOption = $('#selectId option:first');
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然后,您可以获取选项值firstOption.val();或选项文本firstOption.text();
并将其设置为选中:
//firstOption.prop('selected', true); since jQuery 1.6 is known to be faster way
firstOption.attr('selected', true);
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编辑:如果您只想设置所选选项,请使用selectedIndex属性:
$('#selectId').attr('selectedIndex', 0);
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