如何在 cdata 中正确使用方括号

Question

This is how my code gets shown in my developer console (Chrome):

<script type="text/javascript">// <!&#091;CDATA&#091;
function hidden(){ 
    document.getElementById("test123").style.visibility = "hidden"; 
} 

document.getElementById("test123").addEventListener("click", hidden);

var banner =document.querySelectorAll('.contactBanner1');
for(var i=0;i<banner.length;i++){ 
    banner&#091;i&#093;.addEventListener('mouseover',hidden,false); 
}
// &#093;&#093;></script>

This is the error I get now: Uncaught SyntaxError: Unexpected token ILLEGAL

How do I correctly use the [ ?

Answer 1

Back when XML was all the rage, people spent a lot of time thinking about their XHTML and XML being parsed by a single XML parser. As such, the XHTML needed to pass XML validation.

But, a problem that can be encountered is when that XHTML includes JavaScript and that JavaScript contains, say, a < meant to mean less-than.

In HTML, XHTML and XML the < means beginning of a start or end tag.

To prevent this, it was recommended that scripts in XHTML have their content marked as Character Data, so that if/when the XML parser got to it, it would effectively ignore special symbols like < (among others).

So, scripts should have been written as:

 <script type="text/javascript">
   //<![CDATA[ 
           // Inside the CDATA < gets ignored


  //]]>
 </script>

Your code doesn't follow this, instead you are providing the Unicode characters for [ and ].

And, lastly, if you are not worried about your JavaScript being parsed as XML, you can just write the more modern version:

 <script>


 </script>