for in

18.  for in concepts is usefull for us no need to mention total number of array

One dimensional array

<  script type  =  "  text  /  javascript  "  >

var x;

var   no_list = new Array();

no_list [ 0 ] = "Saab";

no_list [ 1 ] = "Volvo";

no_list [ 2 ] = "BMW";

for (x in no_list)

  {

  document.write ( no_list [ x ]  +  " < br  / > " ) ;

  }

< / script >

Output:

Saab

Volvo

BMW

it will display all the name inside the no_list array.