print_r() function in javascript

function print_r() in JavaScript, identical to php's print_r() function

function print_r(theObj)
{
   if ( theObj.constructor == Array || theObj.constructor == Object)
   {
     document.write("<ul>")
     for(var p in theObj)
     {
      if( theObj[p].constructor == Array || theObj[p].constructor == Object)
      {
        document.write("<li>["+p+"] =>"+typeof(theObj)+"</li>");
        document.write("<ul>")
        print_r(theObj[p]);
        document.write("</ul>")
      }
      else
      { 
        document.write("<li>["+p+"] =>"+theObj[p]+"</li>");
      }
     }
     document.write("</ul>")
   }
}