When I type this sololearn crashes

Question

Every time I type this code "window.onload = alert('You are a beta te" it crashes in cookie clicker beta. Also when I make a new line at the beginning it crashes too.

Answer 1

That's the second question I found about your code 'cookie clicker beta', without seeing it in your public profile ^^

Anyway... what do you call "crashes"? Where are "typing" this ( bad ) code?

With this:

window.onload = alert('Your are a beta te

You'll get errors... even by "correcting" it as:

window.onload = alert('Your are a beta tester');

As the 'onload' attribute need a function reference/definition ( don't forgot the semi-colon after closing bracket of function, as this is an assignement expression ):

window.onload = function() { alert('Your are a beta tester'); };

... this use definition of an anonymized function, but you can write as well:

function my_onload_event() { alert('Your are a beta tester'); }
window.onload = my_onload_event;

Answer 2

Try to clear the cache of Sololearn's app.
Code playground behaves anyway quite slugghish on mobile.