It's time for regular expressions (which never really felt all that regular to me)!
So, basically there is a simple regular expression that can check for numeric values.
var $regEx = /\d+/g;
Now we take this and use javascripts .match() function and you've got a winner:
var $regEx = /\d+/g;
var $myString = "S0m3 T3xt! W1th Numb3rz";
var $alsoMyString = "Just regular text";
if($myString.match($regEx)) alert("NUMBERS FOUND!");
if($alsoMyString.match($regEx)) alert("NUMBERS FOUND!");
So in the example this uses an if() statement with our match() function (so we get a true/false conditional statement). If a number is found in the string it alerts. If not then you see nothing. You can apply this same method to your own code, but rather than alert you would continue your code. Or you can add an exclamation point in front of the match statement if you want to only continue if no numbers are found.