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About AngularJs ng-change event/directive usage

小云云Original: 2018-05-10 17:23:212551browse

This article mainly introduces the summary of AngularJs ng-change events/commands. The editor thinks it is quite good, so I will share it with you now and give it as a reference. Let’s follow the editor to take a look, I hope it can help everyone.

Definition and Usage

The ng-change directive is used to tell AngularJS what to do when the value of an HTML element changes.

The ng-change directive needs to be used with the ng-model directive.

AngularJS ng-change directive will not override the native onchange event. If this event is triggered, both the ng-change expression and the native onchange event will be executed.

ng-change event is triggered every time the value changes, it does not need to wait for a completed modification process, or wait for the action to lose focus.

ng-change event is only for actual modification of the input box value, not modification through JavaScript.

Syntax

<element ng-change="expression"></element>

d5fd7aea971a85678ba271703566ebfd, 221f08282418e2996498697df914ce4e, and 4750256ae76b6b9d804861d8f69e79d3 elements are supported.
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Parameter value

Value	Description
expression	Execute expression when the element value changes.

Example description: Execute function when the value of the input box changes:

<body ng-app="myApp">

<p ng-controller="myCtrl">
 <input type="text" ng-change="myFunc()" ng-model="myValue" />
 <p>The input field has changed {{count}} times.</p>
</p>

<script>
angular.module(&#39;myApp&#39;, [])
.controller(&#39;myCtrl&#39;, [&#39;$scope&#39;, function($scope) {
 $scope.count = 0;
 $scope.myFunc = function() {
  $scope.count++;
 };
}]);
</script>

</body>

Example description, radio and checkbox

Note: checkbox ng-model is always true or false, not value. Other ng-models default to the value of value

HTML

<h3>Radio 控件测试</h3> 
<p><label> 
  <input type="radio" value="男" name="sex" ng-model="value1" ng-change="radioChecked()" /> 
  男 
 </label> 
 <label> 
  <input type="radio" value="女" name="sex" ng-model="value1" ng-change="radioChecked()" /> 
  女 
 </label></p> 
<h3>checked 控件测试</h3> 
<p><p class="checkbox"> 
  <label> 
   <input name="agree" type="checkbox" value="同意" ng-model="value2" ng-change="checkboxClick()" /> 
   同意协议 
  </label> 
 </p> 
 <p class="checkbox"> 
  <label> 
   <input name="agree" type="checkbox" value="同意2" ng-model="value2" ng-change="checkboxClick()" /> 
   同意协议2 
  </label> 
 </p></p>

JS：

var app = angular.module(&#39;myApp&#39;, []); 
app.controller(&#39;validateCtrl&#39;, function ($scope) { 
 //randio ng-change事件和原始onchange相同 
 //radio ng-model 的值是value 
 $scope.radioChecked = function () { 
  console.info($scope.value1); 
 } 
 //checkbox ng-change事件和原始onchange相同 
 //checkbox ng-model总是是true或false 
 $scope.checkboxClick = function () { 
  console.info($scope.value2); 
 } 
});

Example description , text, select

HTML

<form class="form-horizontal"> 
 <p class="form-group"> 
  <label class="control-label">姓名：</label> 
  <input type="text" class="form-control" ng-model="name" ng-change="txtChange();" /> 
 </p> 
 <p class="form-group"> 
  <label class="control-label">选择年级：</label> 
  <select class="form-control" ng-change="selectChange();" ng-model="grade"> 
   <option value="1">一年级</option> 
   <option value="2">二年级</option> 
  </select> 
 </p> 
</form>

var app = angular.module(&#39;myApp&#39;, []); 
app.controller(&#39;validateCtrl&#39;, function ($scope) { 
 //textbox 的ng-change事件和原始ng-change不相同，而是和$scope.$watch()监听相同 
 //textbox 的ng-model为当前输入框的内容，为value值 
 $scope.txtChange = function () { 
  console.info($scope.name); 
 } 
 //select 的ng-change事件和原始ng-change相同 
 //ng-model 的默认情况下ng-model的结果为value值 
 $scope.selectChange = function () { 
  console.info($scope.grade); 
 } 
});

Related recommendations:

Tutorial on the method of controller inheritance in AngularJS

AngularJs Ultimate Shopping Cart Implementation Method

About the implementation of the star rating system of Angularjs rendering using directive

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