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JavaScript jQuery Basics (2014) Creating a Simple Drawing Application Perform: Part 5

Posted by Ravit Ben-Shlush
Ravit Ben-Shlush
3,689 Points

why the dots between mouseMove(), mouseUP(), mouseDown()...

why is it mouseDown().mouseMove().mouseUp() ? why theses functions are not separated?

3 Answers

Justin Iezzi
Justin Iezzi
18,199 Points
Justin Iezzi
Justin Iezzi
18,199 Points

Hi Ravit,

This is a syntax called method chaining. Method chaining is used to invoke multiple methods at once. Gregory Schier wrote a really nice article about this on his blog, see here. You can also find many other resources regarding method chaining via Google.

Pavle Lucic
Pavle Lucic
10,801 Points
Pavle Lucic
Pavle Lucic
10,801 Points

It is called method chaining, where a method returns the object which it called it.

Ravit Ben-Shlush
Ravit Ben-Shlush
3,689 Points
Ravit Ben-Shlush
Ravit Ben-Shlush
3,689 Points

the order should matter, right?

Pavle Lucic
Pavle Lucic
10,801 Points
Pavle Lucic
Pavle Lucic
10,801 Points

In this example, answer is no. 

.mouseup( handler )
handler
Type: Function( Event eventObject )
A function to execute each time the event is triggered.

This is from jquery docs.

Important part is handler. By that I mean what function will execute on mouse up.