JavaScript Class Define And Enumerating or Printing Properties

//create a class
function Person(name, age) {  
     this.name = name || "";  
     this.age = age || 0;
}
Person.prototype = new Person;
var john = new Person("John", 29);// add some custom properties
john.language = "English";
john.wife = "Mary";//Enumerate using the standard forEach method:
   
  for(prop in john)
  {
   str+=prop + " value :"+ john[prop]+"\n";//Concate prop and its value from object
  }
  alert(str);

or

var obj = objFrm.elements["name"];
  
  var str=""; //variable which will hold property values
  for(prop in obj)
  {
   alert(prop);
   str+=prop + " value :"+ obj[prop]+"\n";//Concate prop and its value from object
  }
  alert(str); //Show all properties and its value