For the past few years I have always used a client-side hidden <input> field to store a server-side value and use it in Javascript land.
For example, let's say I need an Ajax timeout value from my app configuration.
I'd probably store it like this in my JSP:
<input type="hidden" id="ajaxTimeout" value="${serverValue}" />
and then use it like this where my AJAX call lived in an external file:
$("#ajaxTimeout").val()
I was having a discussion about this today and it was suggested that it is best practice to store values which are only going to be used by Javascript within HTML <meta> tags.
Does this matter? Is there a preferred way to obtain server-side information which is solely to be used in Javascript?
My understanding is that if the hidden input field is not part of a form then it is safe enough to use to store value as it won't be attached to any requests. Having said that, I've always thought this was indeed a bit of a hack.
Thoughts?
::EDIT::
Two fantastic answers:
- Use objects literals for general in-page data that is not tied to any particular DOM element.
- Use data attributes to store custom data tied to DOM elements: http://www.w3.org/TR/2010/WD-html5-20101019/elements.html#attr-data