Nextion language question

How do I make a logical AND gate so the satment is true when j0.val is between 50 and 75 in the nextoin software?

This is not the right way:
if(j0.val>50&&j0.val<75)
{
j0.pco=63488
}

Hello mikastrup,
Welcome to the forum. Please read 'how to use this forum - please read', especially item #7 about posting code. Thank you.

I had this moved from 'using Nextion displays with Arduino' because it is a stand alone question about Nextion, it is not about the tutorial.

Assuming you have a progress bar on your Nextion with objectname j0 then the code compiles OK and works as expected.

When I try it if j0.val is greater than 50 and less than 75, then causing the code to run makes the progress bar red.

What I suspect you are doing, but I don't know as I can't see your HMI file, is expecting the code to run immediately you change j0.val to some value between 51 and 74; this won't work. Something has to trigger the code. In order to test I created a progress bar with the code under Touch Press Event, used the debug window, changed j0.val to 60 then clicked on the progress bar, the progress bar went red as expected, and did not go red if j0.val was less than 51 or more than 74.

If that doesn't tell you what you want to know then you are going to have to be more specific about what you are doing, what you are expecting and what you are getting instead.