The dangers of using the ampersand in XML
The ampersand symbol (&) has an important role in HTML, as it’s used to encode the e-mail address of someone mentioned in a sentence, for example: John Smith & Sons Plumbing. But did you know that the ampersand also has a very special role in XML? And did you know that using it in the wrong place can cause your XML document to be invalid? This article will take you through everything you need to know about using the ampersand in XML and help you avoid errors in your XML documents.
What is XML?
XML is a markup language that is used to store and transport data. It is similar to HTML, but instead of displaying data, it stores data. One of the main benefits of XML is that it is human-readable. This means that it is easy for people to read and understand XML documents. However, this also means that XML documents can be very long and difficult to parse.
What does ampersand mean?
An ampersand is a character that represents the word and. It is often used in place of the word and in shortenings, such as & for and. However, when used in XML, it can create problems. Let’s say you have a sentence: This sentence contains an ampersand. If you try to enter this into an XML file, the system will see that there are no opening or closing tags on either side of the ampersand. The system will not know where one sentence ends and another begins, so it cannot parse your document correctly. Instead, you should use quotation marks to signify where each sentence starts and ends: This sentence contains an ampersand.
Why do I need to avoid it?
If you use an ampersand (&) in your XML, it will create what is called an entity reference. This means that the characters that follow the ampersand will be interpreted as a character reference, and if they are not valid, it will cause an error. Some browsers, like Chrome, might even ignore this behavior and just display the string — which may lead to all sorts of problems down the line.
This can be easily avoided by removing the ampersand or by substituting them with entities (e.g., &). Once again, if you’re curious about more details on entities, check out my previous blog post Don’t Mix Your Code With Characters.
How do I avoid it?
When creating XML documents, it is important to be aware of the dangers of using the ampersand character (&). If not used correctly, it can lead to invalid XML documents that will cause errors when trying to parse them. There are a few ways to avoid this problem . One way is to simply replace all instances of & with & (ampersands surrounded by both single quotes and double quotes). Another option is to put any text with an ampersand character in between CDATA tags (contained data), which prevents that text from being parsed as an XML element.
Example 1
If you’re not careful, using the ampersand can create some serious problems in your XML documents. For one thing, it can create invalid code that won’t be recognized by your software. Even worse, it can cause data loss if you’re not careful. A good example is when it’s used as a delimiter in text values.
If you put an ampersand at the end of a value and then add another value to the document, when parsed the second value will overwrite everything following the first and last character on that line with what is after the ampersand. So even though there are multiple lines between these two values they’ll only appear on one line when parsed (example: VALUE1&VALUE2).
Practice exercise: Avoid & Use Ampersands In XML
If you’re working with XML, you need to be careful of using the ampersand. The ampersand is a reserved character in XML, which means it has a specific meaning. If you use it incorrectly, it can cause your XML to become invalid. When editing an XML document, make sure you replace & signs with < and & signs with >.
You can also remove all occurrences of these characters from the text editor’s configuration file. After making changes, save and close the file. Make sure that no more than one instance of these characters appears in any single line in your XML document.
