You can create with javascript some css-rules, which you can later use in your styles: http://jsfiddle.net/ARTsinn/vKbda/
var addRule = (function (sheet) {
if(!sheet) return;
return function (selector, styles) {
if (sheet.insertRule) return sheet.insertRule(selector + " {" + styles + "}", sheet.cssRules.length);
if (sheet.addRule) return sheet.addRule(selector, styles);
}
}(document.styleSheets[document.styleSheets.length - 1]));
var i = 101;
while (i--) {
addRule("[data-width='" + i + "%']", "width:" + i + "%");
}
This creates 100 pseudo-selectors like this:
[data-width='1%'] { width: 1%; }
[data-width='2%'] { width: 2%; }
[data-width='3%'] { width: 3%; }
...
[data-width='100%'] { width: 100%; }
Note: This is a bit offtopic, and not really what you (or someone) wants, but maybe helpful.