<style>

#myDIV{

    width:150px;

    height:100px;

    background-color:lightblue;

    border:1px solid black;

}

</style>

<p>点击“尝试一下”按钮。让 DIV 元素中的长单词换行到下一行：</p>

<div id="myDIV">Thiscouldbeaninsainlylargeword</div>

<button onclick="myFunction()">尝试一下</button>

<script>

function myFunction(){

    document.getElementById("myDIV").style.wordWrap = "break-word";

}

</script>

​