将任何字符串与开头的p匹配
要使用javascriptregexp匹配任何以p开头的字符串，请使用^pQuantifier-
示例
<html>
<head>
<title>JavaScript Regular Expression</title>
</head>
<body>
<script>
var myStr = "Welcome to our website. We Learners!";
var reg = /^We/g;
var match = myStr.match(reg);
document.write(match);
</script>
</body>
</html>