Variable inside a regex

Hi all,

I am trying to put inside a regex a variable but I cannot get the right results I want.

I want to remove 40 characters from the string “stringToSend”, but if I add the variable “characterLength” inside the regex, it doesn’t work.

If I just add the integer 40 inside the regex, everything works fine.

How can I add that variable “characterLength” inside the regex rightly?

[code]
<script>
var stringToSend = ‘9615f3837cf791fc4302a00ab4adb32dd4171b1e_00004.jpg’;
var characterLength = 40;
var regexVar = new RegExp(/^w{‘ + characterLength + ‘}_/); // this regex doesn’t work
// var regexVar = new RegExp(/^w{40}_/); // this regex is working
outputString = stringToSend.replace(regexVar, ”);
outputString = outputString.replace(/.[^/.]+$/, ”);

console.log(outputString); // Wanted output: 00004
</script>
[/code]

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