error in validation string of simple registration form - javascript

//Javascript code snippet 
function validateName(){
    var name = document.getElementById("fp").value;
    var rel = /^[a-zA-Z\s\'\-']{2,15}$/;

    if(rel.test(name)){
        document.getElementById("namePrompt").style.color = "green";
        document.getElementById("namePrompt").innerHTML = "<strong>valid</strong>";
        return true;
    }
    else{
        document.getElementById("namePrompt").style.color = "red";
        document.getElementById("namePrompt").innerHTML = "<strong>Enter 2-15 characters</strong>";
        return false;
    }
}

This is the above code of my validation i am getting error in " var rel = /^[a-zA-Z\s'-']{2,15}$/; " is there anything wrong with it?