Script for page load time, passing time to variable

Good day to all

I’m looking for a page loading script, but not a simple one… hunting without any type of jquery, only on js, again without additional files and libraries. You can find one on the internet, but here’s the problem… I don’t need to display the page load time, I just need to equate it to a variable (say, to $load_time), and I’ll decide for myself whether I need it “echo ” or not. Does anyone have one?

Answer 1, authority 100%

not suitable

$load_time_start = mktime();
$load_time = mktime() - $load_time_start;