vue里面的v-bind三元表达式

<h2>v-bind</h2>
<h2 v-bind:class="g">V-bind  demo</h2>
<h2 v-bind:class="{red:off}">接收判断条件</h2>
<h2 v-bind:class="{r,g}">{r:r, red:red}</h2>
<h2 :class="[r,g]">绑定数组</h2>
<h2 :class="off ? 'red':'green'">三元表达式</h2>

off:false,