var select_dept = document.getElementById("_deptid"); 
var opt = select_dept = opt.getElementsByTagName("option");
for(var i = 0 ; i < opt.length ; i ++){ //遍历option数组
 if(opt[i].value.indexOf(typeName1) != -1){  //如果值等于目标值，则选中目标值
 opt[i].selected = true;
 break;           
}          
}