Javascript 更新与表达式相关的文本框的值

我想更新angularjs中关于表达式的文本框的值，请检查以下代码

<td><input type="text" ng-model="entry.sale_qty" required  style="width: 200px" ></td>
<td><input type="text" ng-model="entry.sale_price" required  style="width: 200px"></td>
<td><span> <input type="number" ng-model="entry.sale_amount" required>
          {{entry.sale_price*entry.sale_qty|number}}
</span> </td>`

{{entry.sale_price*entry.sale_qty|number}
`

---

表达式生成的值应填充到第三个文本框中？？？

您需要将其分配给另一个范围变量

<input type="number" ng-model="entry.sale_amount = entry.sale_qty * entry.sale_price" required>

更改您的html

<div ng-controller="testController">

<td><input type="text" ng-model="entry.sale_qty" required  style="width: 200px" ng-change="updateVal(entry.sale_qty)"></td>

<td><input type="text" ng-model="entry.sale_price" required  style="width: 200px" ng-change="updateVal2(entry.sale_price)" ></td>

<td><span> <input type="number" ng-model="entry.sale_amount" required>
      {{entry.sale_amount}}
</span> </td>

</div>

function testController($scope) {
$scope.entry={
    sale_qty:'',
    sale_price:'',
    sale_amount:''
};

$scope.updateVal = function(val) {
 $scope.entry.sale_amount=val*$scope.entry.sale_price;
};

$scope.updateVal2 = function(val) {
 $scope.entry.sale_amount=val*$scope.entry.sale_qty;
};

}