The tool allows you to generate Regex expression code for javascript PHP go JAVA rb python language.
You could test your Regex expression here: Regex expression tester online, then use this tool to generate codes for using.
For examples, Match letter regex expression is ^[a-zA-z]*$
The tool will generate javascript Regex code:
var pattern = /^[a-zA-z]*$/, str = ''; console.log(pattern.test(str));
The code you will use in webpage could be
<script> var pattern = /^[a-zA-z]*$/, str = ''; console.log(pattern.test(str)); var str = 'abcdefgABCDEFG'; var result = str.match(re); document.writeln(result == null ? 'error<br><br>' : result[0] + '<br><br>'); </script>