Access CSS file contents via JavaScript

With that specific example (where the CSS is on the same origin as the page), you could read the file as text via ajax:

$.ajax({
    url: "/path/to/file.css",
    dataType: "text",
    success: function(cssText) {
        // cssText will be a string containing the text of the file
    }
});

If you want to access the information in a more structured way, document.styleSheets is an array of the style sheets associated with the document. Each style sheet has a property called cssRules (or just rules on some browsers), which is an array of the text of each rule in the style sheet. Each rule has a cssText property. So you could loop through those, e.g.:

$.each(document.styleSheets, function(sheetIndex, sheet) {
    console.log("Looking at styleSheet[" + sheetIndex + "]:");
    $.each(sheet.cssRules || sheet.rules, function(ruleIndex, rule) {
        console.log("rule[" + ruleIndex + "]: " + rule.cssText);
    });
});

Live example – That example has one stylesheet with two rules.