JavaScript regular expression ( alphanumeric characters with _-)

Question

I am having trouble forming regular expression containing all alphanumeric characters and one or two specific characters, such us _ or - .

This expression works for all alphanumeric characters /^[0-9a-zA-Z]+$/ .

Answer 1

Add the special characters inside the square brackets

/^[0-9a-zA-Z_-]+$/

To use this regex in javascript use this code ( yourPhrase is the string you check vs the regexp)

var rexp = /^[0-9a-zA-Z_-]+$/
if(rexp.test(yourPhrase)){
    //code to handle the test
}

Answer 2

Try this:

/^[0-9a-zA-Z-_]+$/

If you enter the dash sign "-" at a position where it can be interpreted as a range such as _- it would mean any characters matching _ or above in the ascii table.