SetInterval function is not working with PHP File

Question

I have index.html like this

Answer 1

It´s working for me, but you only can see the content one time, because .load function is replacing the old content, change

$('#mydiv').load('xyz.php').fadeIn("slow");  

with this

$('#mydiv').append($('<div >').load('xyz.php'));

Answer 2

I renamed index.html to index.php and called that by localhost/firstproject/index.php. That worked