如何制作base64重定向链接

Question

我有重定向链接，但不是base64，

我的Javascript

var urlAlias = "example[dot]com"; //CHANGE THIS TO YOU WEBSITE

function go() {

x = document.theform.nick.value;

if(x.length < 11)
{
  return 0;
}

var displayURL = x.replace("http://", "");

y = document.location.search.substring(1,11);
y = "";

document.theform.thelink1.value = "http://"+urlAlias+"/?" + x + "" + y;
document.theform.thelink2.value = "<a href=\"http://"+urlAlias+"/?" + x + "" + y + "\">" + displayURL + "</a>";
document.theform.thelink3.value = "[url=http://"+urlAlias+"/?" + x  + "" + y + "]" + displayURL + "[/url]";

return false;

}

我的PHP

<form name=\"theform\" onSubmit=\"return go();\" action=\"#\">
            <fieldset>
                <h3>Your URL:</h3>

                <input class=\"anonym_input\" type=\"text\" maxlength=\"255\" name=\"nick\" value=\"http://\" />
                <input class=\"anonym_FormSubmit\" type=\"button\" onClick=javascript:go() value=\"Generate URL\"/><br /><br />

                <h3>This is the anonymous URL:</h3>
                <textarea class=\"anonym_textarea\" name=\"thelink1\" wrap=\"soft\" cols=\"66\" rows=\"1\" style=\"height: 30px; overflow: auto;\"></textarea><br />
                <br /><h3>This is the anonymous URL as an HTML link:</h3>
                <textarea class=\"anonym_textarea_big\" name=\"thelink2\" wrap=\"soft\" cols=\"66\" rows=\"1\" style=\"height: 30px; overflow: auto;\"></textarea><br />
                <br /><h3>This is the anonymous URL as a board link (works with any board software):</h3>

                <textarea class=\"anonym_textarea_big\" name=\"thelink3\" wrap=\"soft\" cols=\"66\" rows=\"1\" style=\"height: 30px; overflow: auto;\"></textarea><br />

            </fieldset>
        </form>

结果

thelink1= example[dot]com/?stackoverflow[dot]com/
thelink2= <a href="example[dot]com/?stackoverflow[dot]com/">stackoverflow[dot]com/</a>
thelink3= [url=example[dot]com/?stackoverflow[dot]com/]stackoverflow[dot]com/[/url]

我的问题

如何使x = document.theform.nick.value;成为base64编码？

感谢先进：）