Version 4 (modified by Frederico Caldeira Knabben, 16 years ago) (diff)


Coding Style Guidelines

Those guidelines where defined based on mixed common standards mainly related to Java and C# programming.

It is quite common to take the Java style to write JavaScript code, assuming it is a "cut-down" version of Java. Although JavaScript has an indirect relation with Java, apart from the similar "C style" syntax, it has nothing to do with it. It is not a class based language. It is an interpreted, object based, loosely typed scripting language. It can run only in the presence of a "host" application, like a web browser.

If we instead take a closer look at C# code standards (from Microsoft), we'll not more modern and readable proposals, which help also on identifying custom code from the underlying host environment.

The following definitions are based on long years of experience with pure JavaScript coding.

General Recommendations

Any violation to the guide is allowed if it enhances readability.

The name "FCKeditor" is used, it must always be written with "FCK" uppercased concatened with "editor" in lowercase. The following are wrong: "FckEditor", "FCKEditor", "fckEditor", "FCK Editor", and so on. Exception is made for directory names, where all chars "should" be in lowercase.

The name "JavaScript" should be written with both the "J" and "S" in uppercase. The following are wrong: "Javascript", "javascript", etc.

Naming Conventions

Generic Name Conventions

Names representing packages must be in CamelCase. Whenever applicable, the package name will be prefixed with "FCKeditor.".

    FCKeditor, FCKeditor.Net, FCKeditor.Java

Names representing public classes and public global objects must be in CamelCase and prefixed with "FCK".

    FCKBrowserInfo, FCKToolbarButton

Names representing constants must be all uppercase.


Names representing public methods must be verbs and written in CamelCase.

    AppendStyleSheet(), GetElementDocument(), SetTimeout()

Names representing public properties must be verbs and written in CamelCase.

    Name, Document, TargetWindow

Names representing private methods must be verbs and written in CamelCase prefixed with an underscore.


Names representing private properties must be verbs and written in CamelCase prefixed with an underscore.

    _InternalCounter, _Prefix

Names representing private global function must be in CamelCase prefixed with an underscore.

    function _DoSomething()

Abbreviations and acronyms should not be uppercase when used as name.

    SetHtml(), XmlDocument
    SetHTML(), XMLDocument

All names should be written in English.

Specific Name Conventions

The prefixes "Get" and "Set" may be used on methods that get or set properties which require computation.

    SetArrayCount(), GetFormattedValue()

The prefix "CheckIs" may be used on methods which return boolean states which require computation.

    CheckIsValid(), CheckIsEmpty()

Abbreviations in names should be avoided.

    GetDirectoryName(), applicationCommand
    GetDirName(), appCmd


All files must be named in all lower case.

Classes and global objects should be declared in individual files with the file name matching the class/object name.

    fckbrowserinfo.js, fcktoolbarbutton.js


For indentation, the TAB should be used. Development IDEs should be configured to represent TABs as 4 spaces.

    if ( test )
        if ( otherTest )
            DoSomething() ;
        DoMore() ;

Block layout should be as illustrated.

    while ( !done )
        doSomething() ;
        done = moreToDo() ;

Single statement if/else/while/for could (preferably) be written without brackets, but never in the same line.

    if ( condition )
        statement ;

    while ( condition )
        statement ;

    for ( initialization ; condition ; update )
        statement ;

The incompleteness of split lines must be made obvious.

    totalSum = a + b + c + 
        d + e ; 

    method( param1, param2,
        param3 ) ; 

    setText( 'Long line split' + 
        'into two parts.' ) ;


Conventional operators should be surrounded by a space (including ternary operators).

    if ( i > 3 && test == 'yes' )

Commas should be followed by a space.

    function MyFunction( parm1, param2, param3 )

Semi-colons in for statements should be surrounded by a space.

    for ( var i = 0 ; i < count ; i++ )

Semi-colons should be preceded by a space.

    DoSomething() ;
    var name = 'John' ;

Colons should be surrounded by a space.

    case 100 :
    case 100:

Opening parenthesis must be followed by a space and closing parenthesis must be preceded by a space.

   if ( myVar == 1 )

Functions/method calls should not be followed by a space.

    DoSomething( someParameter ) ;
    doSomething ( someParameter ) ;

Logical units within a block should be separated by one blank line.

    // Create a new identity matrix
    var matrix = new Matrix4x4() ;

    // Precompute angles for efficiency 
    var cosAngle = MathCos(angle) ;
    var sinAngle = MathSin(angle) ;

    // Specify matrix as a rotation transformation 
    matrix.SetElement( 1, 1, cosAngle ) ;
    matrix.setElement( 1, 2, sinAngle ) ; 
    matrix.setElement( 2, 1, -sinAngle ) ;
    matrix.setElement( 2, 2, cosAngle ) ;

    // Apply rotation
    transformation.multiply( matrix ) ;


Variables must be always defined with "var".

Function parameters must be in pascalCase.

    function Sum( firstNumber, secondNumber )

Local variables must be in pascalCase.

    function DoSomething()
        var colorOne = 1 ;
        var colorTwo = 2 ;

        return colorOne + colorTwo ;


Tricky code should not be commented but rewritten: In general, the use of comments should be minimized by making the code self-documenting by appropriate name choices and an explicit logical structure.

All comments should be written in English.

There should be a space after the comment identifier.

    // This is a comment     NOT: //This is a comment 
    /**                      NOT: /** 
     * This is block               *This is a block 
     * comment                     *comment 
     */                            */

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