/**
* 实现select切换直接跳转页面效果,对应的html如下：
*	<form method="get" action="#" name="form1" class="form1">
*		<select name="links-select1" onchange="jumpmenu('form1','links-select1','_blank');">
*			<option value="http://www.baidu.com/">菜单1</option>
*			<option value="http://www.baidu.com/">菜单2</option>
*		</select>
*	</form>
* 
* onchange中的函数调用：form1是select所在的form的name值、links-select1是当前select的name值，_blank是链接跳转方式
*/
function jumpmenu(formName, popupName, target) {
    var popup = document[formName].elements[popupName];
    if (popup.options[popup.selectedIndex].value != "") {
        window.open(popup.options[popup.selectedIndex].value, target);
        popup.selectedIndex=0;
    }
}