Error parsing XHTML: The content of elements must consist of well-formed character data or markup

As an extension of this question, I'm trying to insert Javascript to a <h:commandButton />'s onclick property as action is already rendering an ajax table.

What I want to do: Get the selected items in a list box and turn them into parameters to be used in a JSF FileServlet. i.e. para2=value1&param=value2&param=value3

Here's what I have:

<script type ="text/javascript">
function myScript() {
    var box = document.getElementbyId('myForm:box');
    var length = box.options.length;
    var paramstring = "";
    for (var i = 0; i < length; i++) {
        if (i != (length - 1) {
            if (box.options[i].selected) {
                paramstring = paramstring + "param=" + box.options[i].value + "&amp;";
            }
        } else {
            paramstring = paramstring + "param=" + box.options[i].value;
        }
    }
    if (document.getElementById('myForm:checkbox').checked) {
        window.location='fileServlet? + paramstring;
    }
}
</script>  

What I get when page is loaded: javax.servlet.ServletException: Error Parsing /page.xhtml: Error Traced[line:15] The content of elements must consist of well-formed character data or markup.

What doesn't trigger exception:

<script type ="text/javascript">
function myScript() {
    var box = document.getElementbyId('myForm:box');
    var length = box.options.length;
    var paramstring = "";

    if (document.getElementById('myForm:checkbox').checked) {
        window.location='fileServlet? + paramstring;
    }
}
</script> 

As soon as I add in for (var i = 0; i < length; i++) or even for (var i = 0; i < 10; i++) the page wouldn't load. Why does it not like the for loop?

Solution 1:

Facelets is a XML based view technology which uses XHTML+XML to generate HTML output. XML has five special characters which has special treatment by the XML parser:

• < the start of a tag.
• > the end of a tag.
• " the start and end of an attribute value.
• ' the alternative start and end of an attribute value.
• & the start of an entity (which ends with ;).

In case of <, the XML parser is implicitly looking for the tag name and the end tag >. However, in your particular case, you were using < as a JavaScript operator, not as an XML entity. This totally explains the XML parsing error you got:

The content of elements must consist of well-formed character data or markup.

In essence, you're writing JavaScript code in the wrong place, a XML document instead of a JS file, so you should be escaping all XML special characters accordingly. The < must be escaped as <.

So, essentially, the

for (var i = 0; i < length; i++) {

must become

for (var i = 0; i < length; i++) {

to make it XML-valid.

However, this makes the JavaScript code harder to read and maintain. As stated in Mozilla Developer Network's excellent document Writing JavaScript for XHTML, you should be placing the JavaScript code in a character data (CDATA) block. Thus, in JSF terms, that would be:

<h:outputScript>
    <![CDATA[
        // ...
    ]]>
</h:outputScript>

The XML parser will interpret the block's contents as "plain vanilla" character data and not as XML and hence interpret the XML special characters "as-is".

But, much better is to just put the JS code in its own JS file which you include by <script src>, or in JSF terms, the <h:outputScript>.

<h:outputScript name="functions.js" target="head" />

This way you don't need to worry about XML-special characters in your JS code. Additional advantage is that this gives the browser the opportunity to cache the JS file so that average response size is smaller.

See also:

• The entity name must immediately follow the '&' in the entity reference
• Is it possible to use JSF+Facelets with HTML 4/5?
• How to reference CSS / JS / image resource in Facelets template?
• Writing JavaScript for XHTML

Solution 2:

I ran across this post today as I was running into the same issue and had the same problem of the javascript not running with the CDATA tags listed above. I corrected the CDATA tags to look like:

<script type="text/javascript">
//<![CDATA[ 

your javascript code here

//]]>
</script>

Then everything worked perfectly!