Some basic on Javascript that not all programmers are aware

These are some of the JavaScript way of writing that one usually do not know by learning on some basic web site such as w3schoo.com

Declaring many variables at once

You can declare many variable at once by doing the following,

var test,test1,test2,test3,test4
OR
var test=1,test1=2,test2=3,test3=4,test4=5

Assignment operator shortcuts

you can do a assignment operator in short instead of writing long code.

x+3=x -> 1+=3
x-4=-x -> x-=4
x*1=x -> x*= 1
x/1=x -> x/=1
x+1=x -> x++
x-1=x -> x--

The “with” statement

The ‘with’ statement basically help you reduce some code. The meaning of with can be read as ‘with this’. For example,

<script type="text/javascript">
document.write('Hi there, how are you?")
document.write('Fine, thanks. And you?')
document.write('Great!')
</script>

You can write as

<script type="text/javascript">
with(document)
{
write('Hi there, how are you?")
write('Fine, thanks. And you?')
write('Great!')
}
</script>

By using the ‘with’ statement, everything that falls inside of its brackets ({ }) default to the object specified in it’s parameter. That way, you only need to type the object name once.

Remember, the “with” statement can be used with any JavaScript object to avoid having to repeatedly write the object out when referencing it multiple times.

The “?” conditional expression statement

This is a shortcut for if-else statement and it will return a Boolean value. For example, instead of writing this

if(x==1)
do something..
else
don't do it..

We can write something shorter such as this,

x==1 ? do something.. : don't do it..

The format for this is as follow,

(condition) ? doiftrue : doiffalse

Conclusion

The reason for doing all these shortcut is to improve efficiency of the code to help improve performances. Especially on large application where efficiency holds a key to whether its a good or bad application. Every line of code contribute greatly on the performance of the application. One will have to remember that speed in web application holds a key on whether anyone will visit or use your application/site.

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