<div>标签为什么不能像<p>标签那样自动换行

<div>div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1div1HAHAHA</div>
<div>div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2div2 HAHAHA</div>
<p>段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1段落1</p>

结果是下面的图，为什么<div>标签不会像<p>标签那样字数太多了自动换行？还有就是div1字段后面加了HAHAHA但不能显示出来，然而div2字段后面是空格+HAHAHA，这样能显示出HAHAHA但却吃掉了一些div2