JScript Blog : VWD

JScript errors as warnings in Visual Studio 2008 RTM

rneela — Mon, 31 Dec 2007 09:00:00 GMT

Now Visual Studio 2008 code named Orcas is out of door with incredible features. The most highly anticipated feature of this release is JScript Authoring Services which includes JavaScript Intellisense and JavaScript Syntax Checking.

In the final version of Visual Studio 2008, with default profile settings VS shows all JScript/JavaScript syntax errors as warnings and warnings as messages because of which customer will end up unnoticed JScript Syntax Checking feature.

To view JScript Errors as Errors in Error List window enable below option from Options dialog of Visual Studio

- Launch Options dialog by clicking on Tool à Options menu

- Expand Text Editor à HTML à Validation

- Clear Show errors “as warnings (JScript)” check box

This has been added after VS 2008 Beta2 after considering customer feedback. In Visual Studio 2005 and Visual Web Developer Express 2005 all markup and CSS validation related issues such as unsupported tags and attributes are shown as errors in Error List. Few like it since validation errors encourage standard compliance while few didn't want validation errors to show up in Error list as these errors are browser errors. The same applies for JScript errors in VS 2008. This has been addressed by adding above option in the final version of Visual Studio 2008.

Writing for JScript Intellisense in VS 2008

Sameerch — Thu, 08 Nov 2007 09:15:00 GMT

Since we release JSript intellisense in Visual Studio 2008 Beta 2, there has been some queries on why JScript intellisense behaves in a certain way. I wish to tell you that intellisense in a dynamic language like JScript is based on certain heuristics. We try our best to guess the runtime behavior and provide what we think is the best guess. As such, it is not always what a user might expect.

To illustrate, consider the following example:

 1: Person = function() {
 2:     this.name = “Anonymous”;
 3: }
 4:
 5: Person.prototype = {
 6:     getName : function() {
 7:         return this.name;               // I don’t see “name” on the list
 8:     }
 9: }

When we type “this.” In line 7, we don’t see “name” in the intellisense dropdown that pops up. This is contrary to what a user might expect. But consider the following usage:

10: Person.prototype.getName();

In this case, we get an undefined value since “name” is not defined in this context. So, it is not always the case that “name” would be defined. To avoid such ambiguity, the above can be modified so that all variables are defined in the prototype:

11: Person = function() { }
12:
13: Person.prototype = {
14:     name : “Anonymous”,
15:     getName : function() {
16:         return this.name;               // I see “name” on the list now
17:     }
18: }

Now, you can see “name” in the intellisense drop down.

Update 11/12/2007: There have been some recent comments on this post which rightly point out that there is a functionality difference between the two. The difference is subtle. And, if you are unsure of the functionality difference , I would suggest that you start by reading this post on Classes in Jscript by Ritesh.

Sameer

Javascript Intellisense and Coloring Issues in VS 2008 Beta 2

Sameerch — Mon, 24 Sep 2007 22:30:00 GMT

We have come across a couple of installation issues in VS 2008 Beta 2 which broke the new Javascript functionalities in certain scenarios. While a workaround has already been provided in the online refresh of the ReadMe text, I thought I would also put it down here in case any of you hit the problem.

Issues

We faced two installation issues which broke Jscript functionality in VS 2008 Beta 2

Uninstallation of Silverlight Tools for Visual Studio 2008 Beta 1 removes the Jscript Authoring DLL
Installation of Team Explorer Beta 2 corrupts the registration of Jscript

In either case, you dont get to see Javascript intellisense, syntax errors, and javascript coloring does not work.

Workaround

The recommended workaround for both the issues is to Repair the Visual Studio installation by running setup again. The first issue can be avoided by uninstalling SL Tools for VS Beta1 before installing VS 2008 Beta 2. The second issue can also be fixed if you dont mind fiddling with the registry. See the blog post here for details.

Sameer

JScript Syntax Check in Visual Web Developer 2008 Beta2

don.raman — Fri, 03 Aug 2007 12:56:00 GMT

Visual Web Developer 2008 Beta2 got announced some days back. Lots of authoring enhancement has been made to this release so far as JScript is considered. Sameer already blogged about much better intellisense support in this release. I would like to point out that we also had a brand new support for Syntax Checking with this release. Syntax Checking is a very helpful feature and helps a JScript developer to find out the errors/warnings in his code at design time. The goal was to make life of a JScript developer a lot easier. We feel this is going to make a very good impact on the developers.

Let's say while writing the code I defined a variable twice. Isn't it cool the editor catching up the mistake for me? This is exactly what happens. Look at the snapshot below:

As one can see the moment the user makes a mistake, squiggles are shown and on taking the mouse over the squiggle the error/warning is displayed. User is saved from all the hassles of actually running the code to find out all the annoying errors/warnings. All the errors/warnings get listed down even in the error window as shown below:

This gives a detailed error/warning message and double clicking actually takes you to the line number.

Some of the other facts I would like to list are:

A syntax error or warning does not stop other authoring features like syntax coloring and intellisense to stop working. The parser used is a recovery parser which throws off/ignores bad tokens and continue giving authoring support.
This only catches the error/warning detectable by parser. A runtime error will not be detected by this and you will get the error running the application.
The syntax checking is also available in the stand alone JScript file added to your web project.
This feature is also available in the Express edition of Visual Web Developer 2008.

So go ahead and start using the new Beta2 available and give your feedback to us.

Don Raman

Senior Test Lead

Jscript debugging: Stepwise instructions and video

rajesh.bhutani@microsoft.com — Tue, 24 Apr 2007 09:05:00 GMT

If you are interested in debugging your Jscript code, then you can use Visual Web Developer (VWD) Express edition, a free download from Microsoft website. Exact instruction on how to use VWD for debugging Jscript are listed at the following blog post:

http://blogs.msdn.com/rajeshbhutani/archive/2007/04/10/debugging-jscript-code-in-ie-using-vwd-express.aspx

If you want to see these steps in action then you can watch the following screencast:

http://channel9.msdn.com/ShowPost.aspx?PostID=301814