Hello,
please use the correct encoding for values in html-tags.
if you only encode the & you can hijack your code like this.
?test=%22/%3E%3Cscript%3Ealert(/test/);%3C/script%3E&page=%5Bpage%5D
You will also generate a not
I think this
en.wikipedia.org/wiki/HTML#Attribut ...
should help you.
best regard
Tom