【Angular】二级联动：如何从js二级联动，下拉框内容为动态查询

一、思路

①分别写两个各自独立的下拉框，互不影响；

②在父级下拉框里写一个ng-change方法，当父级下拉框的选中值变化时，调用方法；

③把父级选中的id或值传给子级下拉框，动态查询；

二、代码

1-1 html源码：

<label class="col-lg-1 control-label" for="major">专业</label>
<div class="col-lg-2">
<select   class="input-sm form-control" name="id" id="major"
ng-options="option.id as option.name for option in majorList"
ng-model="q.majorId" ng-change="professionChange()">
</select>
</div>

<label class="col-lg-1 control-label" for="position">岗位</label>
<div class="col-lg-2">
<select class="input-sm form-control" name="id" id="position"
ng-options="option.id as option.name for option in positionList"
ng-model="q.positionId">

</select>
</div>

1-2 html截图；



2-1js代码：

/*专业初始化初始化：warn 必须初始化具体*/
$scope.majorList = [
{ id:0 ,name:"1"}
];

/*岗位初始化：position*/
$scope.positionList = [
{ id:0 ,name:"2"}
];

questionService.getMajorType().then(
function (res) {
/*清空*/
$scope.majorList = [];
for (var i = 0; i < res.data.length; i++) {
/*初始化*/
var majorSingleOption= {
id:res.data[i].id,
name: res.data[i].name
};
$scope.majorList.push(majorSingleOption);

}

}
);

/*当下拉选项变化的时候*/
$scope.professionChange=function () {
var index=document.getElementById("major").selectedIndex;//获取当前选择项的索引.
$scope.proChoosedId=document.getElementById("major").options[index].value;//获取当前选择项的值.
var num = $scope.proChoosedId.replace(/[^0-9]/ig,"");
questionService.getPositionType({professionId:num}).then(
function (res) {
$scope.positionList= [];
for (var i = 0; i < res.data.length; i++) {
/*初始化*/
var positionSingleOption = {
id:res.data[i].id,
name: res.data[i].positionName
};
$scope.positionList.push(positionSingleOption);
}

}
);
};

2-2js截图

三、总结

①获取选中的父级下拉框内的id，通过改id来查询其子选项；

var index=document.getElementById("major").selectedIndex;//获取当前选择项的索引.
$scope.proChoosedId=document.getElementById("major").options[index].value;//获取当前选择项的值.

②从字符串中提取数字（正则）：

var num = $scope.proChoosedId.replace(/[^0-9]/ig,"");