后台怎么调用调用前台js函数值

var time = new Date().getTime();

            function _c(s, k) {

                var m = window.event;

                var _s = s.split("");

                var t = _t(s, k);

                var f = _f(s, t);

                return _d(_s, f)

            }

            function _t(s, k) {

                var l = String(k).length;

                var _t = String(k).substring(l - 4, l);

                while (_t.length < s.length) {

                    _t += _t

                } return _t

            }

            function _f(s, k) {

                var _f = new Array(s.length);

                for (var i = 0; i < s.length; i++) {

                    var t = k.split("");

                    _f[i] = t[s.length - 1 - i]

                }

                return _f

            }

            function _d(s, k) {

                var e = new Array();

                var fe = "";

                for (var i = 0; i < s.length; i++) {

                    e[i] = String(_e(s[i], k[i], i + 1));

                    fe += e[i]

                } return fe

            };

            function _e(s, k, n) {

                if (window.closed) {

                    n = 0; k = 0

                }

                var e = parseInt(s, 36) + parseInt(k, 36) + n;

                if (e >= 36) {

                    e = e - 36

                }

                return e.toString(36)

            };

context.Response.ContentType = "application/json";

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context.Response.Write(str);