Javascript example
HTML
<input type="submit" id="byBtn" value="Foo" onclick="foobar()"/>JavaScript
function foobar(){
var str = "Este aqui Ă© o valor do cliente 000.000.00 01";
var old = str.match(/\d\d\d\.\d\d\d\.\d\d \d\d/);
var to_replace = "129.000.000 02";
var new_str = str.replace(/\d\d\d\.\d\d\d\.\d\d \d\d/g, to_replace);
alert("Valor original: " + old);
alert("Novo valor: " + to_replace);
}