url 怎么解码？

%3cmms%3e%3csubject%3e5o6M5o%2bh5ZWG5py65omL5py65oql%3c%2fsubject%3e%3cpages%3e%3cpage+dur%3d%2210%22%3e%3cimg+type%3d%22gif%22%3eR0lGODlhsAC0AMQAADhliWee4KrS%2bIydsdDp%2b3229P7%2b%2fiVMf5bF9hkUJObz%2fUx0mMrc%2bMrT3G9zeAIlUitlz%2bDs%2b%2fX6%2ftvg5rfAzO%2f3%2fbne%2bvDz%2bEWA3Pr8%2fQRVqezt8RdNyS44QCxef%2f%2f%2f%2fyH5BAAAAAAALAAAAACwALQAAAX%2f4CeOZGmeaKqubOu%2bcCzPdG3feK7vfO%2f%2fwKBwSCwaj8ikcslsOp%2fQ6MkAM1A%2f12A2dd1WRV0wViytUr2oc9g61oVV7DGapGa%2f0%2bWYZ8%2fv%2b%2f%
像这样代码。 里面其它是文本和图片
现在怎么把解码变成文本和图片?

JScript code

alert(unescape("%3cmms%3e%3csubject%3e5o6M5o%2bh5ZWG5py65omL5py65oql%3c%2fsubject%3e%3cpages%3e%3cpage+dur%3d%2210%22%3e%3cimg+type%3d%22gif%22%3eR0lGODlhsAC0AMQAADhliWee4KrS%2bIydsdDp%2b3229P7%2b%2fiVMf5bF9hkUJObz%2fUx0mMrc%2bMrT3G9zeAIlUitlz%2bDs%2b%2fX6%2ftvg5rfAzO%2f3%2fbne%2bvDz%2bEWA3Pr8%2fQRVqezt8RdNyS44QCxef%2f%2f%2f%2fyH5BAAAAAAALAAAAACwALQAAAX%2f4CeOZGmeaKqubOu%2bcCzPdG3feK7vfO%2f%2fwKBwSCwaj8ikcslsOp%2fQ6MkAM1A%2f12A2dd1WRV0wViytUr2oc9g61oVV7DGapGa%2f0%2bWYZ8%2fv%2b%2f%"));