String.prototype.isEmpty = function(){return /^\s*$/.test(this);}
String.prototype.isNumber = function(){return /^\d*\.?\d{0,4}$/.test(this);}
?
String.prototype.isEmpty = function(){return /^\s*$/.test(this);}
String.prototype.isNumber = function(){return /^\d*\.?\d{0,4}$/.test(this);}
?