PHP中的密码加密等效于C＃

I have this code to encrypt password with md5 and SALT in C#

var encoder = new UTF8Encoding();
var hashedBytes = new MD5CryptoServiceProvider().ComputeHash( encoder.GetBytes( salt + password ) );
return Convert.ToBase64String( hashedBytes );

Now, I want to use same encryption in php but don't know how to do it?

Can anyone help me on this issue?