Suppose I have an URL like this https://example.com?page=1 or have https://example.com?text=1. Here what does mean by ?page=1 or ?text=1. Some website like youtube there I can see that they use like https://youtube.com?watch=zcDchec . What does mean it?
Please explain anyone. I need to know this.
That’s the query component (indicated by the first ?).
It’s a common convention to use key=value pairs, separated by &, in the query component. But it’s up to the author what to use. And it’s up to the author to decide what it should mean.
In practice, the query component ?page=1 will likely point to page 1 of something, while ?page=2 will point to page 2, etc. But there is nothing special about this. The author could as well have used the path component, e.g. /page/1 and /page/2.
