<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<button onclick="replace()">replace</button>
<p id="a">poau,Pula,Paul,PAUL</p>
<script>
function replace() {
var b = document.getElementsById('a').innerHTML;
var c = b.replace("Paul","Ringo");
document.getElementsById("a").innerHTML = c;
}
</script>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<button onclick="replace()">replace</button>
<p id="a">poau,Pula,Paul,PAUL</p>
<script>
function replace() {
var b = document.getElementsById('a').innerHTML;
var c = b.replace("Paul","Ringo");
document.getElementsById("a").innerHTML = c;
}
</script>
</body>
</html>
</html>