However, they are not a number or an alphabet. What you might do is use negative lookaheads to assert your requirements: ^(?![0-9._])(?!.*[0-9._]$)(?!.*\d_)(?!.*_\d)[a-zA-Z0-9_]+$. If you found this post helpful consider giving it a "Thumbs Up.". The next characters can be alphabethic, numeric or special signs only : "-" and "_". I am using this code to validate only entering characters and spaces, but this doesn't work. Can state or city police officers enforce the FCC regulations? is divided in to three components per requirement, The regular To view the purposes they believe they have legitimate interest for, or to object to this data processing use the vendor list link below. The str.replace() method will return a new string with all characters replaced. This pattern can be used to remove the unwanted chars in JS. Quick access. to two components. With an added quantifier that repeats the character class one or more times, and anchors that bind the match to the start and end of the string, were good to go. The same might need to be done for all To remove non-alphanumeric characters from a string, you will first call the replace() method and pass a regular expression (RegEx) that matches all non-alphanumeric characters as the first parameter and an empty string as the second parameter. Otherwise, it returns, . hope that it will match all the numbers from 1 to 100, then your regex More on Python: 10 Ways to Convert Lists to Dictionaries in Python. Regex - to find whole numbers only - problem, Allow only decimal numbers in textbox in C#, How to validate phone numbers using regex. Now Add Answer . The content you requested has been removed. It wont modify the original string. string. In the regex you provided, the lookaheads serves to ensure your string met some specific conditions, but they are not the real filter which keeps out undesired strings. characters that are used byregex, Use "[a-zA-Z]" to allow only latin letters from A to Z, "^[A-Za-z\s]*$" will match "Some text here" but would not match ",,", I also want to allow all special characters like !@#$%^&*()[]{}\_-+=,.<>/?`~/*-+. The regex for To the Button a jQuery click event handler is attached thus when the button is clicked, the TextBox text is validated against the, ="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js">