Very simple parameter subsitution in JS. Arguments are string containing parameter placeholders and a corresponding object of keys and values. Depends on jQ.

param_substitution.js

// Return s, with parameters substituted as in key-values of object params
function subsituteParams(s, params) {
    $.each(params, function(k,v) {
        s = s.replace(k,v);
    });
    return s;
}