I'm not sure that 'let' is fully supported in all browsers, especially IE11 (if you're using it) .

Try omitting the first line altogether.

Thanks Paul for replying.

When I remove the first line, I get the following error -

lead_status jscript error: 'document' is undefined Line: 2 Char: 0
lead_status jscript error: 'document' is undefined Line: 2 Char: 0

This error was what led me to trying to use let document

Thanks Paul for replying.

When I remove the first line, I get the following error -

lead_status jscript error: 'document' is undefined Line: 2 Char: 0
lead_status jscript error: 'document' is undefined Line: 2 Char: 0

This error was what led me to trying to use let document

Is this code in the screen CustomContent?  If so you need to make it run when the page has finished loading:

The marginRight style is for div elements though; "_Datalead_status" is a span so may not have any effect.

(sorry - this stupid website will no longer let me post any code, hence the image.)