How call this javascript hidden field call behind code in asp.net

Hi,
I want javascript hidden field values in behind code, because
now a day we going software audited. I can use hidden field but
he can clear text values. so i can acces this value

function InitializeRequest(path) {
// call server side method
var pwdhfld = document.createElement("INPUT");
pwdhfld.type = "hidden";
pwdhfld.name = "t";

pwdhfld.value = path;
document.forms[0].appendChild(pwdhfld);

PageMethods.SetDownloadPath(path);
}