/** * Add a stylesheet rule to the document (may be better practice, however, * to dynamically change classes, so style information can be kept in * genuine styesheets (and avoid adding extra elements to the DOM)) * Note that an array is needed for declarations and rules since ECMAScript does * not afford a predictable object iteration order and since CSS is * order-dependent (i.e., it is cascading); those without need of * cascading rules could build a more accessor-friendly object-based API. * @param {Array} decls Accepts an array of JSON-encoded declarations * @example addStylesheetRules([ ['h2', // Also accepts a second argument as an array of arrays instead ['color', 'red'], ['background-color', 'green', true] // 'true' for !important rules ], ['.myClass', ['background-color', 'yellow'] ] ]); */ function addStylesheetRules (decls) { var style = document.createElement('style'); document.getElementsByTagName('head')[0].appendChild(style); if (!window.createPopup) { /* For Safari */ style.appendChild(document.createTextNode('')); } var s = document.styleSheets[document.styleSheets.length - 1]; for (var i=0, dl = decls.length; i < dl; i++) { var j = 1, decl = decls[i], selector = decl[0], rulesStr = ''; if (Object.prototype.toString.call(decl[1][0]) === '[object Array]') { decl = decl[1]; j = 0; } for (var rl=decl.length; j < rl; j++) { var rule = decl[j]; rulesStr += rule[0] + ':' + rule[1] + (rule[2] ? ' !important' : '') + ';\n'; } if (s.insertRule) { s.insertRule(selector + '{' + rulesStr + '}', s.cssRules.length); } else { /* IE */ s.addRule(selector, rulesStr, -1); } } }

addStylesheetRules(["div.content", ["color": "#000"], ["border-width","1px"], ["border-style", "solid"]])

<style> div.content{color:#000;border:1px solid} </style

addStylesheetRules( [selector, [attr, value], …], [selector, [attr, value], …] );