Checks if input has illegal characters. I was using it to see if the user already had a valid username.

check-originial-username.js

hasOriginalUsername: function() {

	var illegalChars = new RegExp(/\W/); // allow letters, numbers, and underscores

	if ( illegalChars.test( this.originalUsername ) ) { 

		return true; 

	} else{  

		this.username = this.originalUsername;

		return false; 
	}
}