How to get class in vue.js

vue.js method of obtaining class:

1. Data binding

vue instructions are marked with v- prefix. Data binding instructions v-bind: attribute name, abbreviated as: attribute name. A simple data binding example is as follows:

<a v-bind:href="http://www.php.com/">php中文网</a>
简写：
<a :href="http://www.php.com/">php中文网</a>

2 , the delimiter of dynamic binding class

vue is {{ }} by default. The string in the delimiter will be considered as a data variable, which can be passed class="{{ className }}" method to set class, but vue does not recommend mixing this method with v-bind:class method, you can only choose one of the two. Although v-bind:class cannot coexist with the method of binding variables in the class attribute, it can coexist with the native class feature. The native class and v-bind:class are allowed to appear at the same time in a DOM tag.

2.1 v-bind:class Supports string type. It is not recommended to use it because the string value is fixed and cannot dynamically change the class.

HTML代码：
<div :class=" &#39;classA classB&#39; ">Demo1</div>
渲染后的HTML:
<div class="classA classB">Demo1</div>

2.2 v-bind:class supports data variables. When the variable value changes, the class will be updated at the same time. v-bind:classThe value of the directive is limited to a binding expression, such as a javascript expression.

HTML代码：
<div :class="classA">Demo2</div>
Javascript代码：
data: {
  classA: &#39;class-a&#39;  //当classA改变时将更新class
}
渲染后的HTML:
<div class="class-a">Demo2</div>

The value written in the directive will be regarded as an expression, such as a javascript expression. Therefore v-bind:class accepts ternary operations:

HTML代码：
<div :class="classA ? &#39;class-a&#39; : &#39;class-b&#39; ">Demo3</div>
渲染后的HTML:
<div class="class-a">Demo3</div>

2.3 v-bind:class supports objects, and class will be dynamically updated when the object changes

HTML code:

<div :class="{ &#39;class-a&#39;: isA, &#39;class-b&#39;: isB}">Demo4</div>
Javascript代码：
data: {
  isA: false,  //当isA改变时，将更新class
  isB: true    //当isB改变时，将更新class
}
渲染后的HTML:
<div class="class-b">Demo4</div>

HTML代码：
<div :class="objectClass">Demo5</div>
Javascript代码：
data: {
  objectClass: {
    class-a: true,
    class-b: false
  }
}
渲染后的HTML:
<div class="class-a">Demo5</div>

2.4: v-bind:classSupports arrays. When the variables in the array change, the class list will be dynamically updated

HTML代码：
<div :class="[classA, classB]">Demo6</div>
Javascript代码：
data: {
  classA: &#39;class-a&#39;,
  classB: &#39;class-b&#39;
}
渲染后的HTML:
<div class="class-a class-b">Demo6</div>

The array can contain the object type. When the object object changes, the class list will also be updated

HTML代码：
<div :class="[classA, classB]">Demo7</div>
Javascript代码：
data: {
  classA: &#39;class-a&#39;,
  objectClass: {
    classB: &#39;class-b&#39;,  // classB 的值为class-b, 则将classB的值添加到class列表
    classC: false,    // classC值为false,将不添加classC
    classD: true    // classD 值为true，classC将被直接添加到class列表
}
}
渲染后的HTML:
<div class="class-a class-b classD">Demo7</div>