CSS, Salesforce, ExtJS, and the blues

Question

I've been asked to demo some ExtJS UI enhancements to our current apps inside Salesforce. This is just a proof of concept that ExtJS will work as a good UI replacement for the default UI that most of our VisualForce pages use.

Everything works great, that is, except a few odds and ends of the CSS. There are lots of styles inside "...visual.force.com/sCSS/21.0/sprites/13013.../Theme3/default" that are messing with the ExtJS elements. Specifically commmon.css and extended.css. Here's an example:

Extended.css

body .x-date-middle, .x-date-left, .x-date-right {
    background: none repeat scroll 0 0 transparent;
}

Is there an elegant way around this, or is ExtJS just not going to play well inside of Salesforce?

For example: Is there a way that I can tell my VisualForce page to ignore commmon.css and extended.css?

Answer 1

Do you need the standard Salesforce style sheets? If not, you can use the showHeader and standardStylesheets attributes to stop Salesforce from sending down the style sheets.

<apex:page standardStylesheets="false" showHeader="false">
</apex:page>

Answer 2

I can't speak to whatever Salesforce is doing, but if Ext's styles are being overridden (by any other CSS really) you have two choices: remove the offending CSS, or override the rules yourself. Not much way around that in Ext 3.x.

In Ext 4 you'll be able to sandbox your Ext styles by customizing the global Ext.baseCSSPrefix config, which will effectively eliminate this issue going forward.