Wednesday, August 22, 2007

cfajaxproxy and the head tag

*** UPDATE ***

Ok, so slight modification. It appears that your JavaScript only has to appear after the opening <head> tag. And, this only applies to JavaScript that makes calls against the JavaScript proxy generated by the cfajaxproxy tag (Any other JavaScript can appear anywhere you want). However, if you are going to make JavaScript calls against the proxy generated by the cfajaxproxy tag, then you had better do them after the opening <head> tag.

One other caveat: The above only applies to pages with a <head> tag. If your page doesn't have a <head> tag, then you can put any of your JavaScript anywhere you want. The above only applies to pages with a <head> tag.

It would take too long to explain why the JavaScript behaves this way. However, if anyone wants to know the reason that I believe the JavaScript behaves this way, let me know, and I will post it. It has more to do with where ColdFusion posts its JavaScript on the page than with any quirks in the JavaScript itself.

*** END UPDATE ***

Recent experience has shown that the JavaScript proxy generated by cfajaxproxy will not work if you have any user-generated JavaScript that appears outside of the <head> tag. For example, consider the following pages:

Here is the main page:
<!-------- index.cfm -------->

<cfajaxproxy cfc="component.cfc" jsclassname="component_proxy">

<script>

var js_component_proxy = new component_proxy();

var result = js_component_proxy.a_function();

</script>

<cfinclude template="top.cfm">

Some content

<cfinclude template="bottom.cfm">

<-------- End index.cfm -------->

The "Top" include follows. Notice that it has the HTML header in it.
<!-------- start.cfm -------->

<html>

<head>

Header Content

</head>

<body>

<!-------- End start.cfm -------->

And a nice little bottom.cfm to tie everything up nicely.
<-------- end.cfm -------->

</body>

</html>

<-------- End end.cfm -------->

The above will not work. When you run the JavaScript generated by cfajaxproxy, you will get the following JavaScript error:

window:global: mark_arrived has no properties


However, if you copy the user generated JavaScript into the header area marked "Header Content", suddenly everything works fine.

This was a bit of a problem for us. Our site has a page similar to the "start.cfm" page mentioned here, that in addition to many other things, contains the page header data. This means that cfajaxproxy will not work for us if we use any other JavaScript on the page.

We did find a moderately painless workaround. If anyone is interested, post a comment, and I will post the workaround here.

2 comments:

jones said...

Nice blog...
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Anonymous said...

Thanks for the good, practical advice. I would be interested in the workaround.