Failed to call function from external javascript

[tsabboi3]

I want to use javascript to check for the \[code\]radio button\[/code\] whether is checked or not.If the \[code\]tidak setuju\[/code\] radio button is checked or \[code\]setuju\[/code\] radio button is not checked, I want to \[code\]alert\[/code\] a dialog box.But somehow the \[code\]onclick\[/code\] function at the \[code\]submit\[/code\] button is not working.I temporarily uploaded my page to a free server.Here is my site, and this is the external javascript file.What is wrong with my code?