Event order in Client-side

If an element and one of its ancestors have an event handler for the same event, which one should fire first?” Not surprisingly, this depends on the browser.


The basic problem is very simple. Suppose you have a element inside an element

-----------------------------------
| element1 |
| ------------------------- |
| |element2 | |
| ------------------------- |
| |
-----------------------------------
and both have an onClick event handler. If the user clicks on element2 he causes a click event in both element1 and element2. But which event fires first? Which event handler should be executed first? What, in other words, is the event order?

Answers

•Netscape said that the event on element1 takes place first. This is called event capturing.
•Microsoft maintained that the event on element2 takes precedence. This is called event bubbling.

The two event orders are radically opposed. Explorer only supports event bubbling. Mozilla, Opera 7 and Konqueror support both. Older Opera's and iCab support neither.

Event capturing
When you use event capturing

| |
---------------| |-----------------
| element1 | | |
| -----------| |----------- |
| |element2 \ / | |
| ------------------------- |
| Event CAPTURING |
-----------------------------------
the event handler of element1 fires first, the event handler of element2 fires last.

Event bubbling
When you use event bubbling

/ \
---------------| |-------------
| element1 | | |
| -----------| |--------- |
| |element2 | | | |
| ----------------------- |
| Event BUBBLING |
-------------------------------
the event handler of element2 fires first, the event handler of element1 fires last.

Comments

Post a Comment

Popular posts from this blog

Interview Questions to Ask the Employer

It's your turn! As the interview comes to a close, one of the final questions you may be asked is "What can I answer for you?" Have interview questions of your own ready to ask. You aren't simply trying to get this job - you are also interviewing the employer to assess whether this company and the position are a good fit for you. Here are questions to ask the interviewer so you can ensure the company is a good match for your qualifications and interests. How would you describe the responsibilities of the position? How would you describe a typical week/day in this position? Is this a new position? If not, what did the previous employee go on to do? What is the company's management style? Who does this position report to? If I am offered the position, can I meet him/her? How many people work in this office/department? How much travel is expected? Is relocation a possibility? What is the typical work week? Is overtime expected? What are the prospects for growth and a...
Read more

Place .NET DLL in GAC

Today other team guy has asked me help as he was facing some problem in trying to place a .NET DLL in GAC where he does not have source code with him. Potentially you just have to follow regular steps as mentioned below to place the DLL in GAC; 1. Generating the public key: Go to visualStudio.Net command prompt and type the following command: sn -k keyfile1.snk Here keyfile1.snk is the keyfile we are generating. You can store this key file in the bin folder of the assembly. In order to do this u have to go to the bin folder. For example: C:\foldername\assemblyname\bin sn-k keyfile1.snk By doing this the keyfile is stored in the bin folder. 2. Than place the keyfile into the Assembly. Go to AssemblyInfo.cs file: [assembly: AssemblyKeyFile("C:\foldername\assemblyname\keyfile1.snk")] 3. Then build the Assembly. 4. Placing the assembly into GAC This process is fine when you have source code with you. What if you don't have the source code with you and you need to put it to t...
Read more

Windows Communication Foundation - FAQ

Image
Difference between Web Service and WCF? Major Difference is That Web Services Use XmlSerializer But WCF Uses DataContractSerializer which is better in Performance as Compared to XmlSerializer. Key issues with XmlSerializer to serialize .NET types to XML Only Public fields or Properties of .NET types can be translated into XML. Only the classes which implement IEnumerable interface. Classes that implement the IDictionary interface, such as Hash table can not be serialized. The DataContractAttribute can be applied to the class or a strcture. DataMemberAttribute can be applied to field or a property and theses fields or properties can be either public or private. Web Services : 1.It Can be accessed only over HTTP 2.It works in stateless environment WCF : WCF is flexible because its services can be hosted in different types of applications. The following lists several common scenarios for hosting WCF services; IIS WAS Self-hosting Managed Windows Service Important difference ...
Read more