Something

var iEC = document.createElement('div');

iEC.innerHTML = '<div id="iec" style="position:absolute;width:500px;height:500px;top:0;left:45%">'+
					'<div style="background:#444 none repeat scroll 0%; height:25px;'+
					'text-align:center;font-size:11px;color:white" id="iecdrag">#########</div>'+
					'<textarea id="iecTa" style="width:500px;height:500px;padding:10px;oveflow:auto;">'+
					'</textarea><div style="clear:both;"></div><button id="applyCSS" style="float:left;">Apply Changes</button></div>';


document.getElementsByTagName('body')[0].appendChild(iEC);

var dS = document.styleSheets;		

var iecTA = document.getElementById('iecTa');
					
for(var i=0;i<dS.length;i++){
	
	(iecTA.value == "")? iecTA.value = dS[i].cssText: iecTA.value = iecTA.value+dS[i].cssText;
	
	if(i>0){
		
		dS[0].cssText = dS[0].cssText+dS[i].cssText;
		
		dS[i].disabled = true;
		
	}

};

document.getElementById('applyCSS').attachEvent('onclick',function() {
	
	dS[0].cssText = iecTA.value;
	
	dS[0].disabled = false;

});