Function length property

Each function has two properties: length and prototype. The length property indicates the number of named arguments that the function expects:

 
<!DOCTYPE html>
<html>
<head>
    <title>Example</title>
    <script type="text/javascript">
        function sayName(name){ 
            document.writeln(name); 
        } 
        
        function sum(num1, num2){ 
            return num1 + num2; 
        } 
        
        function sayHi(){ 
        } 
        document.writeln("hi"); 
        document.writeln(sayName.length); //1 
        document.writeln(sum.length); //2 
        document.writeln(sayHi.length); //0 
        
       
    </script>
</head>
<body>
</body>
</html>
Click to view the demo
Home 
  JavaScript Book 
    Essential Types  

Function:
  1. The Function Type
  2. Function Declarations versus Function Expressions
  3. Functions as Values
  4. Returning a function from a function
  5. Function arguments
  6. this for function context
  7. Function caller
  8. Function length property
  9. Function apply()
  10. Function.call() method
  11. Function's bind() method
  12. Function toLocaleString() and toString()