To match any string with p at the beginning of it with JavaScript RegExp, use the ^p Quantifier −
Example
<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>