What is asynchronous commit, ajax asynchronous commit, and synchronous commit

Solved the problem Favorite**To QQ space What is asynchronous submission [ Tags:async,Commit ] I'm doing **The process said,Seeing such a statement,I hope professionals can help Feilong :1 Popularity:

1 Solve time:2010-04-10 21:20 Satisfactory answer: Asynchronous transfer is a character-oriented transmission, and its unit is character; Synchronous transmission is a bit-oriented transmission, its unit is zhen, and it requires that the clocks of the receiver and sender are consistent when transmitting.

Specifically, asynchronous transfer is the transfer of bits into small groups. Generally each group is an 8-bit character, and there is a start bit and a stop bit at the head and tail of each group, and the clocks of the receiver and sender are not required to be the same during transmission, that is, the sender can send these groups at any time, and the receiver does not know when it will arrive. One of the most obvious examples is the communication between the computer keyboard and the host, pressing a key at the same time to send an 8-bit ASCII code to the host, the keyboard can send ** at any time, depending on the user's input speed, the internal hardware must be able to receive a typed character at any time.

This is a typical asynchronous transfer process. One potential problem with asynchronous transfers is that the receiver doesn't know when the data will arrive. Before it detects the data and responds, the first bit has passed.

It's like someone coming up from behind to talk to you unexpectedly, and you don't have time to react and miss the first few words. Thus, each asynchronous transfer of information begins with a start bit, which informs the receiver that the data has arrived, which gives the receiver time to respond, receive, and cache data bits; At the end of the transmission, a stop bit indicates the termination of the transmitted information. By convention, an idle (no data transmitting) line actually carries a signal representing a binary 1.

The start bit of the step transmission makes the signal 0, and the other bits make the signal change with the transmitted data information. Finally, the stop bit causes the signal to change back to 1, which remains on hold until the next start bit is reached. For example, if the number "1" on the keyboard is encoded according to the 8-bit extended ASCII, "00110001" will be transmitted, and a start bit needs to be added before the 8-bit bit and a stop bit after it.

The concept of asynchronous submission is too broad, there are data, there are pulses, there are magnetic fields, there are currents, there are optical fibers, and so on. Anyway, it's an asynchronous back-and-forth transmission. It's like playing **, you talk about me, I listen to me, you listen to you again.

1. ajax

I don't need to explain this.

2. iframe

This is commonly used when uploading files asynchronously.

3. img

Submit simple data in the GET mode. You can use the onload event to check the result.

4.script tag.

Submit simple data in the GET mode. The results can be obtained in the way of **.

From the user's experience, of course, it is good to be asynchronous, because the page does not need to wait, and the user can continue to operate when the system communicates asynchronously, but it is necessary to pay attention to control and not cause data errors due to operation.

The way to submit data is asynchronous and synchronous, asynchronous submission data can also be submitted with multiple data, splicing the data string that needs to be communicated, the so-called synchronous submission is probably the form function with submit to submit it, click the button to directly submit the content of the entire form, which will cause the entire page to refresh.

Asynchronous submission is very good for user experience, but it is slightly more troublesome than form submission, and the submitted data string needs to be spliced by itself, and if it is troublesome, you can also use JQEURY's serialize method to output serialized form values.

That's about it.

The difference between asynchronous requests and synchronous requests.

That's it for a simple understanding.

Synchronization requests. Browser - > send request - > server processing - > send response - > browser asynchronous request.

Browser - > send request - > browser.

The request is processed > the server and > sends a response.

Responsive - > browser.

For asynchronous requests, as long as the browser sends it, it will not wait for the server's response, it will be refreshed or redirected, and JS will be used to process the response when the server response arrives.

There are several differences:

1.AJAX is submitted, requested, and received asynchronously, and the web page does not need to be refreshed.

Form submission is to create a new page, even if it is a page submitted to yourself, it also needs to be refreshed;

2.aWhen submitting, a new request is created in the background;

f is to abandon the page and then request it;

3.A must use JS to implement, and browsers that do not enable JS cannot complete this operation;

f is the instinct of the browser, whether js is turned on or not, you can submit the form;

4.aWhen submitting, requesting, receiving, the whole process requires the use of programs to process their data;

When submitted, it is automatically completed according to the structure of your form, without the need for **intervention;

For the time being, I only thought of the above points.

The form is sent out and it doesn't matter.

ajax is sent out and taken care of later.

Ajax, an ajaxform that leverages jquery

Step 1: Add a form first.

Step 2: and the inclusion of the file.