selector 1.selector 从单词的意思来说:选择者,选择器,就是对你的目标的控制. 从API来说: A controller for the selection of SelectableChannel objects. Selectable channels can be registered with a selector and get a SelectionKey that represents the registration. The keys are also add
//**1.设置选中值:(根据索引确定选中值)**// var osel=document.getElementById("selID"); //得到select的ID var opts=osel.getElementsByTagName("option");//得到数组option var obt=document.getElementById("bt"); obt.onclick=function(){ opts[3].selected=tr