JavaScript | Print all properties of Object

To Print all properties of an object in JavaScript, use for-in as follows:

<script language="Javascript">
 var obj = new Object();  //Create new object
 obj["firstName"]="Davendra"; //Assign property firstName with value Davendra
 obj["lastName"]="Upreti";       //Assign property lastName with value Upreti
 var str="";         //variable which will hold property values
 for(prop in obj)
 {
  str+=prop + " value :"+ obj[prop]+"\n"; //Concate prop and its value from object
 }
 alert(str);   //Show all properties and its value
</script>