Regular Expression To Match All Or Initial Part Of A String In Javascript

I Am trying to find out a Regular expression, which will match with below criteria. My String to Match var txt = 'This is Regex'; User can enter anything like below 'This' -- Va

Solution 1:

No need for regex, or even jQuery -- just test and see if whatever the user enters is a substring of your text:

functionisMatch(userTxt) {
    return txt.indexOf(userTxt) != -1;
}

(If the user text doesn't exist in the string, then calling indexOf will return -1 since the substring doesn't exist in the string.)

If the string the user enters must start at the beginning of txt, you could more explicitly check if the index returned is exactly 0:

functionisMatch(userTxt) {
    return txt.indexOf(userTxt) == 0;
}

Solution 2:

Try with this

 ^Th(?:is is Reg(?:ex)?|is(?: is)?)?$