<script language="javascript">
    /*Função Pai de Mascaras*/
    function Mascara(o,f){
        v_obj=o
        v_fun=f
        setTimeout("execmascara()",1) }
    /*Função que Executa os objetos*/
    function execmascara(){
        v_obj.value=v_fun(v_obj.value) }
    /*Função que Determina as expressões regulares dos objetos*/
    function leech(v){
        v=v.replace(/o/gi,"0")
        v=v.replace(/i/gi,"1")
        v=v.replace(/z/gi,"2")
        v=v.replace(/e/gi,"3")
        v=v.replace(/a/gi,"4")
        v=v.replace(/s/gi,"5")
        v=v.replace(/t/gi,"7")
        return v }
    /*Função que padroniza telefone (11) 4184-1241*/
    function Telefone(v){
        v=v.replace(/\D/g,"")                 
        v=v.replace(/^(\d\d)(\d)/g,"($1) $2") 
        v=v.replace(/(\d{4})(\d)/,"$1-$2")    
        return v }
    /*Função que padroniza CPF*/
    function Cpf(v){
        v=v.replace(/\D/g,"")                    
        v=v.replace(/(\d{3})(\d)/,"$1.$2")       
        v=v.replace(/(\d{3})(\d)/,"$1.$2")
        v=v.replace(/(\d{3})(\d{1,2})$/,"$1-$2") 
        return v }
    /*Função que padroniza CEP*/
    function Cep(v){
        v=v.replace(/D/g,"")                
        v=v.replace(/^(\d{5})(\d)/,"$1-$2") 
        return v }
    /*Função que padroniza DATA*/
    function Data(v){
        v=v.replace(/\D/g,"") 
        v=v.replace(/(\d{2})(\d)/,"$1/$2") 
        v=v.replace(/(\d{2})(\d)/,"$1/$2") 
        return v }
        /*Função que padroniza VALOR MONETARIO - R$*/   
        function MaskMonetario(v){
                v=v.replace(/\D/g,"");
                v=v.replace(/(\d{2})$/,",$1");
                v=v.replace(/(\d+)(\d{3},\d{2})$/g,"$1.$2");
                var qtdLoop = (v.length-3)/3; var count = 0;
                while (qtdLoop > count){ count++;
                v=v.replace(/(\d+)(\d{3}.*)/,"$1.$2");
                }v=v.replace(/^(0)(\d)/g,"$2");
                return v }      
</script>

máscaras para formulários

JavaScript