Please use the [jass] and [trigger] tags
trigger tag
Jass tag

JASS:
function DoSomething takes unit u returns location
return GetUnitLoc(u)
endfunction
function Na takes nothing returns nothing
local effect fx=AddSpecialEffect("boo\\ba.mdl", DoSomething(GetTriggerUnit()))
call DestroyEffect(fx)
endfunction
JASS tag - Errors and highlight
The jass tag has 2 features to add more functionality, some times you want to point out an error or put more strength to some text, you can place errors between # # and things to highlight between @ @

JASS:
call SetUnitPositionLoc(u, GetUnitLoc(ou) )
call SetUnitPosition(u, GetUnitX(ou), GetUnitY(ou) )
The code that generated the above code block is:
[jass]
call SetUnitPositionLoc(u, #GetUnitLoc(ou)# )
call SetUnitPosition(u, @GetUnitX(ou), GetUnitY(ou)@ )
[/jass]
JASS tag - JASS extensions
As a way to officiallize a preprocessor syntax that was the result of some kind of agreement, //! is considered preprocessor directive by the JASS tag.

JASS:
//! include something.j
function blah takes nothing returns nothing
The keywords static, struct and endstruct are also highlighted
Inline JASS tag [ljass]
Sometimes you only need highlight for a single line and a whole block is too much, for example:
call DoNothing()
Initially collapsed JASS tag
You may want to make your script begin collapsed, then use the hiddenjass instead of the jasstag
[hiddenjass=My Function]function myfunction takes nothing returns real
return 56.3
endfunction
[/hiddenjass]

My Function:
function myfunction takes nothing returns real
return 56.3
endfunction