如果有很多同一个类，如何使用JavaScript获取特定元素？

Question

I have this code. How can I get 'a' of 'div1' :

<div id="div1">
    <div class="a"></div>
    <div class="b"></div>
</div>
<div id="div2">
    <div class="a"></div>
    <div class="b"></div>
</div>

Thanks for help. Just started learning JavaScript.

Answer 1

This should do it:

document.querySelector('#div1 > .a');

• # is the ID selector ; #div matches the element with id="div1"
• > is the child selector
• . is the class selector ; .a matches any element with class="a"

Together, this specifically selects the <div class="a"> element that is a child of <div id="div1"> .