링크 많을때의 경우를 위해 수정 댓글 달면 좋겠네요

<!DOCTYPE html>

<html>

<head>

<style>

body{margin:0px;width:100%;height:100%;}.left{width:10%;height:100%;display:inline;float:left;}.right {width:90%;height:100%;display:inline;float:left;}

</style>

</head>

<body><div class=left>

<h1>The Element Object</h1>

<h2>The innerHTML Property</h2>

<p onclick="myFunction()">Click me to change my HTML content (innerHTML).</p></div><div class=right id="demo">+</div>

<script>

function myFunction() {

  document.getElementById("demo").innerHTML = "I have changed!";

}

</script>

</body>

</html>