Show Alert from JQuery based on server side method return

[shpunsetoy]

I have to call a server side method \[code\]GetMSG\[/code\] using jQuery and that server side method\[code\][WebMethod()]public string GetMSG() { if(condition) { return 'MSG' } else { return '' }}\[/code\]Now using that \[code\]msg\[/code\]I have to show alert. How to use return \[code\]msg\[/code\] and display alert in jQuery.