Função javascript para máscaras(CNPJ, CPF, RG, Telefone)

mask.js

mask("###.###.###-##","12345678900");
mask("##.###.###/####-##","12345678000122");
function mask (pattern,value) {
	var result="";
	var lacCount=-1;
	for(var i=0, max = pattern.length; i< max;i++){
		if(pattern.charAt(i)==='#'){
			lacCount++;
			result+=value[lacCount];
		}else{
			result+=pattern.charAt(i);
		}
	}
	return result;
}