js中如何進行base64編碼

如下是base64編碼：
var str_base64 = "CgkJCgkJCQk8Y29uZGl0aW9ucyB0eXBlPSJBTkQiPgoJCQkJCTxzeXNDb25kaXRpb25zIHR5cGU9Inx8Ij4KCQkJCQk8c3lzQ29uZGl0aW9uIG5hbWU9ItDCzsS1tSIgZXhwcmVzc2lvbj0iS0dselRtVjNSRzlqS0NrcElBPT0iLz4KCQkJCQk8c3lzQ29uZGl0aW9uIG5hbWU9IrWxx7C0psDtyMsiIGV4cHJlc3Npb249IktHbHpRM1Z5VlhObGNpZ3BLU0E9Ii8+CgkJCQkJPC9zeXNDb25kaXRpb25zPgoJCQkJPC9jb25kaXRpb25zPgoJCQk=";

項目引入了[base64.js][1]
var str = Base64.decode(str_base64 ); 
console.log(str);

輸出內(nèi)容如下：(**name中文亂碼**)
//<conditions type="AND">
//    <sysConditions type="||">
//        <sysCondition name="D???μ" expression="KGlzTmV3RG9jKCkpIA=="/>
//        <sysCondition name="μ±?′|àíè?" expression="KGlzQ3VyVXNlcigpKSA="/>
//    </sysConditions>
//</conditions>

怎么通過js解決亂碼問題??? Thanks