var uri="https://www.chunten.com/my test.php?name=ståle&car=saab";
var uri_encode=encodeURIComponent(uri);
document.write(uri_encode);
document.write("<br>");
document.write(decodeURIComponent(uri_encode));

结果：

https%3A%2F%2Fwww.chunten.com%2Fmy%20test.php%3Fname%3Dst%C3%A5le%26car%3Dsaab
https://www.runoob.com/my test.php?name=ståle&car=saab