I don’t think if you are a web developer and you are not aware of firebug but this can be the case that you are a web developer and you are still sticking with the Firefox just because you love firebug and web developer toolbar. Most non-techie people around the globe still love IE (some of them are still on IE6 because that came with their MS Windows XP installation) and they constitute more than 70% of the total, so if you are going to develop for general public or for a client who just couldn’t understand that why I don’t use IE and why Firefox is my favorite browser, you need to have a look at your web application in IE before shipping it and I am telling you it could always go wrong as you may be calling a function whose one parameter Firefox is ignoring and still executing the code while IE wouldn’t ignore and will stall altogether. Luckily, IE8 comes bundled with IE developer tools (developer tools were around from some time but installing them on and off was a real nightmare, at-least for me). But yes I can hear what you are saying, most of the times, IE will throw an error and it will have very “helpful” error description such as “Unspecified Error” and it will point at totally wrong line in the source code and you will have to do your guess work to eliminate the problem, anyway, with developer tools you could see something in place of nothing.
Enough discussion, here is your 3-minutes crack-on graphical tutorial to use IE developer tools just like your native firebug console and web developer toolbar on Firefox.
First load your desired web page in IE8 which you want to inspect by pressing F12 or by selecting Tools > Developer Tools in IE8.
Second always remember that to inspect a script you need to select it first and start debugging. In IE Developer Tools > Script tab > Select script > Start Debugging
Selecting Debugging Source
The most convenient use of firebug for me is of seeing the JS variable values as I develop a complex client-side application. As I discussed above, you don’t want to see alert boxes again and again, IE developer tools, do that for you in two ways.
You can use console to see any output messages. To differentiate between these messages, different console.log APIs are available:
My favorite in firebug was console.debug but I left using that long ago because IE Developer Tools do not support console.debug and this will break your code. Secondly firebug allows you to format those error message, IE Developer Tools do not support that (or at-least something I am not aware of). The output of these console messages will be exactly like something you see in firebug. For the record, you write code like this:
var myvar = 0;
IE Developer Tools Log Messages
The other way is slightly different, can be used for the same purpose but is related to only variables, you are able to see variable values at your breakpoints, so you have the time to analyze them.
To create a break point, hover your mouse on the line number you want to mark as break point and click, a red dot will appear on the left beside the line number, now when you will start debugging, browser will stop executing it just before the line you marked as break point.
Then go to the right hand pane of IE developer tools and select Watch > Click to add the variables you want to see and developer tools will let you know the variable name, value and type at the break point.
Watch variables at break point
You are able to change variable values at this moment as well, just when you are watching a variable in Watch tab, open Console tab and assign new value to the variable to see how it will behave after you hit Play again. In the same manner you are able run any instructions which are not in source code but you want to run them at break point to analyze the effect.
Part 1: Running script at break point
Part 2: IE Developer Tools console with new variable value
Now go back to the Watch tab and see the updated value.
Part 3: Watch updated variable value
Another important need for a web developer who do not think that JS is just a scripting language and it just has bits like getting an element and changing it’s value at run time etc. but it is so important that the developer actually needs to optimize the run times and to see how many times a function is getting called, JS profiler is just what saved our lives in firebug, it is here too in IE Developer Tools.
You need to select Profiler tab in Developer Tools > Start Profiling, do something on your page like refresh or wait for sometime if that is something you want to check and then Stop Profiling, Developer Tools will give you a complete report of JS activity done in that time span, listing Functions, count of the calls made and inclusive, exclusive time etc. Same information can be seen in Call Tree view if you select call tree from Current View.
View Generated Source
If you ever worked with Ajax, you would probably know the importance of seeing the DOM once your Ajax call has been made and your DOM has got updated. In Firefox I use Web Developer Toolbar to see Generated Source, in IE Developer Tools, you can view the same by going into View > Source > DOM, you can view the Original source code and the selected element’s DOM as well.
View Generated Source
Outlining Elements on the Page
Another important tool of firebug is when you can outline the elements on your page to see where they are residing, like the divs or tables etc. I specifically use Web Developer Toolbar instead to outline and see the cause of cosmetic issues. IE Developer Tools comes with this solution as well. You can go to Outline in menu and select the type of elements you want to outline or to select an individual element you can go to Any Element and add the name of the element to view outline.
There are plenty of other functions which Developer Tools support like you can also see the CSS of an individual element by going to Find > Select Element by Click and then clicking on the element, just like you do for inspect element tool in firebug. You can view Images information or disable scripts, CSS, change the browser modes to render the page in IE7, validate your HTML (this will take you straight to W3C website and if you are working on localhost on your system, chances are W3C will refuse to check your code), CSS etc and you can even re size your browser to see your pages in different resolutions.
There is no doubt, Microsoft was under pressure from the developer community to bundle the developer tools with IE because after the arrival of Firefox, the whole development scenario got changed and developers want to develop more rich applications for the web. I personally havn’t adopted IE for my core development but it is handy to check my code every now and then in IE to see if everything is fine there and if not, using Developer Tools makes the life easier by allowing you to debug the code.
Feel free to comment if you have anything to say!