To prevent from XSS attacks, you just have to check and validate properly all user inputted data that you plan on using and dont allow html or javascript code to be inserted from that form.
Or you can you Use htmlspecialchars() to convert HTML characters into HTML entities. So characters like <> that mark the beginning/end of a tag are turned into html entities and you can use strip_tags() to only allow some tags as the function does not strip out harmful attributes like the onclick or onload.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…