Why the W3C Validatior show this ? I don’t know what character use for substitue this " | "
Because strictly speaking, you are not supposed to use pipe characters in URL query strings. But Google does it anyway, and it works fine.
You need to keep in mind that validation is a useful tool for debugging your HTML/CSS, but it is not always the absolute truth. In some situations (and on a lot of websites - try running some of your favourites through the validator!) you’ll come across some validation errors and warning that you’ll just have to live with.
I understud, thanks for help !
You are welcome.