>From the standard[1] the following definition is stated > A prototype is an object used to implement structure, state, and behaviour inheritance in ECMAScript. > When a constructor creates an object, that object implicitly references the constructor’s associated > prototype for the purpose of resolving property references. The constructor’s associated prototype can be > referenced by the program expression constructor.prototype, and properties added to an object’s > prototype are shared, through inheritance, by all objects sharing the prototype.
You can create members and member methods on an object without using the prototype object, however these will not be resolved when the object's constructur is invoked to create an implicit copy of the object. This concept has nothing to do with the namespace, the namespace is simply a clean and neat way of separating code. [1] http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-262.pdf -- Rune V. Sjøen You always pass failure on the way to success On Tue, Dec 1, 2009 at 9:20 AM, codingGirl <[email protected]>wrote: > Thanks for your answer. > > So this is the only way in Javascript to create members, methods and > inheritance? Or do we use this 'prototype' concept because we defined > a namespace? > > On Dec 1, 2:14 am, Rune V. Sjøen <[email protected]> wrote: > > The prototype object is used when you want to add a custom property or > > method to an object and want the changes to be reflected in _all_ the > > instances of it. > > > > example.MyTable.prototype.draw = function(data, options) ... > > > > Without the prototype object the function draw will only apply to that > > particular object. However the goal is to make the draw method exist in > all > > instances of MyTable. > > > > In short, it is the JavaScript way of doing class members, methods and > > inheritance. > > > > -- > > Rune V. Sjøen > > You always pass failure on the way to success > > > > On Tue, Dec 1, 2009 at 1:32 AM, codingGirl > > <[email protected]>wrote: > > > > > I am not a Javascript ninja so this might be a lack of knowledge but > > > that about the 'prototype' objects used in > > >http://code.google.com/apis/visualization/documentation/dev/index.html > > > ? > > > > > Every class-method has a prototype in its name. What does it do? Can I > > > omit it? > > > > > // Declare a unique namespace. > > > var example = {}; > > > > > // Class constructor. Parameter container is a DOM elementon the > > > client that > > > // that will contain the visualization. > > > example.MyTable = function(container) { > > > this.containerElement = container; > > > } > > > > > // Main drawing logic. > > > // Parameters: > > > // data is data to display, type google.visualization.DataTable. > > > // options is a name/value map of options. Our example takes one > > > option. > > > example.MyTable.prototype.draw = function(data, options) { > > > > > // Create an HTML table > > > var showLineNumber = options.showLineNumber; // Boolean > > > configuration option. > > > > > var html = []; > > > html.push('<table border="1">'); > > > > > // Header row > > > html.push('<tr>'); > > > if (showLineNumber) { > > > html.push('<th>Seq</th>'); > > > } > > > for (var col = 0; col < data.getNumberOfColumns(); col++) { > > > html.push('<th>' + this.escapeHtml(data.getColumnLabel(col)) + '</ > > > th>'); > > > } > > > html.push('</tr>'); > > > > > for (var row = 0; row < data.getNumberOfRows(); row++) { > > > html.push('<tr>'); > > > if (showLineNumber) { > > > html.push('<td align="right">', (row + 1), '</td>'); > > > } > > > > > for (var col = 0; col < data.getNumberOfColumns(); col++) { > > > html.push(data.getColumnType(col) == 'number' ? '<td > > > align="right">' : '<td>'); > > > html.push(this.escapeHtml(data.getFormattedValue(row, col))); > > > html.push('</td>'); > > > } > > > html.push('</tr>'); > > > } > > > html.push('</table>'); > > > > > this.containerElement.innerHTML = html.join(''); > > > } > > > > > // Utility function to escape HTML special characters > > > example.MyTable.prototype.escapeHtml = function(text) { > > > if (text == null) > > > return ''; > > > return text.replace(/&/g, '&').replace(/</g, '<') > > > .replace(/>/g, '>').replace(/"/g, '"'); > > > } > > > > > -- > > > > > You received this message because you are subscribed to the Google > Groups > > > "Google Visualization API" group. > > > To post to this group, send email to > > > [email protected]. > > > To unsubscribe from this group, send email to > > > [email protected]<google-visualization-api%[email protected]> > <google-visualization-api%[email protected]<google-visualization-api%[email protected]> > > > > > . > > > For more options, visit this group at > > >http://groups.google.com/group/google-visualization-api?hl=en. > > -- > > You received this message because you are subscribed to the Google Groups > "Google Visualization API" group. > To post to this group, send email to > [email protected]. > To unsubscribe from this group, send email to > [email protected]<google-visualization-api%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/google-visualization-api?hl=en. > > > -- You received this message because you are subscribed to the Google Groups "Google Visualization API" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-visualization-api?hl=en.
