Question

I want to get the styleSheets via document.styleSheets, however, it seems that Firefox will silently ignore some CSS values where they are not illegal. I am now using vh & vw, I want to get the css value and generate the right px for it.

Is there any way to get the values ignored by Firefox?

Answer 1

I do think that Firefox (and maybe other browsers) will return only computed styles from the stylesheets.

However, you could go into a more manual process with selecting the tag you want, make an ajax request to get its text content (will be almost instant since it’s in cache), and parse it.

html:

<link rel="stylesheet" href="style.css" id="css">

js (with jQuery):

$.get($("#css").attr("href"), function(data) //requests the css in ajax
{
   var selector = "div#right", rules = {};

   data = data.substring(data.indexOf(selector)); //trim all that is before your selector
   data = data.substring(data.indexOf("{") + 1, data.indexOf("}")); //get only what's in the curly braces
   data = data.split(";"); //split to get an array with each cell is a css rule

   for (var i = 0, l = data.length; i < l; i++) //loop through
   {
        data[i] = data[i].replace(/^\s+/, ''); //trim spaces before
        data[i] = data[i].replace(/\s+$/, ''); //trim spaces after

        if (data[i].indexOf(':') == -1) { continue; } //if rule is invalid, skip it

        data[i] = data[i].split(':'); //split rule so you have a sub-array with 0:key and 1:value
        rules[data[i][0]] = data[i][1]; //apply it to an object
   }

   console.dir(rules); //here you have. if your rules have "-" in it, you can't access with directly, but with brackets it'll be ok. ie : rules.margin-left is wrong but you can with rules["margin-left"].

}, "text");