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JavaScript Asynchronous Programming with JavaScript What is Asynchronous Programming? Examples of Synchronous and Asynchronous Code

HsinTzu Chen
HsinTzu Chen
5,833 Points

Does send(null) had impact on asynchronous behavior?

I think the synchronous and asynchronous behaviors in first and second example is made by third argument in open method (true: asynchronous or false: synchronous).

However, there is also difference in send method first example (synchronous )-->xhr.send(null) and second example (synchronous )-->xhr.send().

I am wondering if null argument has impact on asynchronous behavior? If not, does anyone knows why null argument is used? Many Thanks!

2 Answers

Steven Parker
Steven Parker
220,425 Points

If you look at the MDN documentation for xhr.send(), you'll find that it says "If no value is specified for the body, a default value of null is used."

So it's simply programmer's preference, either an empty argument or an explicit null will produce the same behavior.

HsinTzu Chen
HsinTzu Chen
5,833 Points

Steven Parker , I see. Next time, I will try to check official document first. Thank you for your explanation!