Why does http 403 forbidden occur when submitting a form?

Question

Apache HTTP Server

When submitting a form, the server returns an error 403. We managed to find out more precisely under what circumstances it occurs, namely, when sending text in any of the fields that begins with "http:/". It is the text that begins just like that. I ask those who know to explain the cause of the problem. Apache/2.2.15 (CentOS)

Answer 1

If the method is GET then try to encode the request with the function escape($('input[type="text"]').val());

Answer 2

The reason is that the web application behind the server handles data in this way. Maybe it's just crooked, maybe there is a built-in WAF.