Href中的PHP Echo切断变量

Question

In my form action:

    <form class="login" style=" ;"method="post" action=<?php echo "add_answer.php?id="; echo $id; echo "&z=$zipcode&d=$date&category=$category"; ?>">

$category is a 2 word variable "lawn mowing". However, it directs me to the link:

add_answer.php?id=1&z=55901&d=04/25/2014&category=Lawn

If you notice the end is "Lawn" instead of "Lawn Mowing" I made sure $category is "Lawn Mowing" as it is displayed in a header on the page. How can I fix this so the whole word is passed through the URL?

Answer 1

You need to urlencode() the variables.

<form class="login" style=" ;"method="post" action=<?php echo "add_answer.php?id=".urlencode($id)."&z=".urlencode($zipcode)."&d=".urlencode($date)."&category=".urlencode($category); ?>">

Why do I have to urlencode() ?

A URI is always in an "escaped" form, since escaping or unescaping a completed URI might change its semantics. Normally, the only time escape encodings can safely be made is when the URI is being created from its component parts; each component may have its own set of characters that are reserved, so only the mechanism responsible for generating or interpreting that component can determine whether or not escaping a character will change its semantics. Likewise, a URI must be separated into its components before the escaped characters within those components can be safely decoded.

In some cases, data that could be represented by an unreserved character may appear escaped; for example, some of the unreserved "mark" characters are automatically escaped by some systems. If the given URI scheme defines a canonicalization algorithm, then unreserved characters may be unescaped according to that algorithm. For example, "%7e" is sometimes used instead of "~" in an http URL path, but the two are equivalent for an http URL.

Because the percent "%" character always has the reserved purpose of being the escape indicator, it must be escaped as "%25" in order to be used as data within a URI. Implementers should be careful not to escape or unescape the same string more than once, since unescaping an already unescaped string might lead to misinterpreting a percent data character as another escaped character, or vice versa in the case of escaping an already escaped string.

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