Listing known CSS classes using Javascript

Question

I'm trying to find a good way to collect the names of classes defined in the stylesheets included with a given document. I know about document.StyleSheetList but it doesn't seem like it'd be easy to parse. What I'm looking for is something like, for a stylesheet document such as:

.my_class { 
    background: #fff000; 
}
.second_class {
    color: #000000;
}

I could extract an array like ["my_class", "second_class"]. This obviously assumes the favorable scenario of a fully loaded dom and stylesheets.

I've been looking everywhere for a good way to do something like this and so far, have made little progress. Does anyone have any idea about how to pull this off? Thanks!

Answer 1

This will show all rules defined in the stylesheets.

var allRules = [];
var sSheetList = document.styleSheets;
for (var sSheet = 0; sSheet < sSheetList.length; sSheet++)
{
    var ruleList = document.styleSheets[sSheet].cssRules;
    for (var rule = 0; rule < ruleList.length; rule ++)
    {
       allRules.push( ruleList[rule].selectorText );
    }
}

The thing, though, is that it includes all rules regardless of being class or tag or id or whatever..

You will need to explain in more detail what you want to happen for non class rules (or combined rules)

Answer 2

You were on track with document.styleSheets (https://developer.mozilla.org/en/DOM/document.styleSheets)

https://developer.mozilla.org/en/DOM/stylesheet.cssRules

Here's a quick and dirty method to output all class selectorTexts to the console in Firefox + Firebug.

    var currentSheet = null;
    var i = 0;
    var j = 0;
    var ruleKey = null;

    //loop through styleSheet(s)
    for(i = 0; i<document.styleSheets.length; i++){
        currentSheet = document.styleSheets[i];

        ///loop through css Rules
        for(j = 0; j< currentSheet.cssRules.length; j++){

            //log selectorText to the console (what you're looking for)
            console.log(currentSheet.cssRules[j].selectorText);

            //uncomment to output all of the cssRule contents
            /*for(var ruleKey in currentSheet.cssRules[j] ){
                 console.log(ruleKey +': ' + currentSheet.cssRules[j][ruleKey ]);
            }*/
        }
    }