对象语法:
<div :class="{ active: isActive }"></div>
<div class="static" :class="{ active: isActive, ‘text-danger‘: hasError }" ></div>
数组语法:
<div :class="[‘defaultClassName‘, errorClass]"></div>
<div :class="[isActive ? activeClass : ‘‘, errorClass]"></div>
<div :class="[{ active: isActive }, errorClass]"></div