! + "\ V1 ″&! + [1,] &!" 1 "[0] faster than anyone else

What we have done below may be a bit of a taste of jumping bones in the eggs, but it is also very interesting. I hope you will be able to gain something after reading it.

In general, browser compatibility issues have plagued developers. hardworking developers have also come up with a variety of tips to differentiate browsers of different factions.

! + "\ V1"
This is what we saw in situ zhengmei's shoes in the garden. At first glance, we were shocked. It turned out that we could be so cool.
The following is my understanding. Source: link 1.
This is a javascript type conversion technique. According to the priority, here is from right to left (+ get positive>! Calculate the negative logic ). that is, convert the string "\ V1" to a number and then reverse it. it is easy to understand the inverse of the number. As long as the values not 0 are true, the + operator converts the string to a number. then, ie is ambiguous here. The Escape Character "\ v" and vertical tab are incorrectly understood. There are more explanations about the Tab character link 2 at the end of the text. the tab can be correctly interpreted in other browsers. ie interprets the tab as the letter "V", which of course cannot be converted to numbers. Naturally, Nan is converted according to the conversion rules of logical operators, if it is converted to false, another reverse request is converted to true, which means "I am IE, yes, true! ".
 

! + [1,]
We also saw it in situ children's shoes, and there were a lot of items to receive from the garden every day. For the explanation of this judgment statement, please move to Situ zhengmei-the shortest ie judgment in the whole world.
However, in the next test, you will find that the minimum statement is not necessarily the fastest.

 

! "1" [0]
This was found when I looked at the ext source code. In the comments of Ext. toarray, the author told IE that the array subscript cannot be used to access the string. Can this be distinguished.
This method is used. In ie, the string cannot be accessed as an array subscript. In ext annotations, the system prompts that "ABC" can be used ". match (/. /g) method, I wondered how to directly use the native split method, "ABC ". split (""), obviously more intuitive, and removes the need for a regular expression.
This method is more efficient than IE in ff.
Note

 

IE8
Judgment statement	Three tests			Average Value
! + "\ V1"	3776	3682	3681	3713
! + [1,]	58422	56519	56581	57174
! "1" [0]	5445	5554	5507	5502
! Window. addeventlistener	23045	22825	22908	22926
Window. attachevent	29419	29450	29556	29475
Document. All	44553	44647	44835	44678
Firefox3.6
! + "\ V1"	1425	1428	1425	1426
! + [1,]	12627	12478	12560	12555
! "1" [0]	125	140	126	130
! Window. addeventlistener	27236	25530	25556	26107
Window. attachevent	77590	79494	77347	78143
Document. All	22877	22984	22978	22946

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Test Environment CPU: e2180 (2.0 GHz), Ram 2G. OS: win7

 

Test code

VaR I = 0, total = 10000000, btimespan, p1timespan, p2timespan;
VaR bstart = new date ();
For (; I <total; I ++ ){
If (/* test statement */);
}
Btimespan = new date (). gettime ()-bstart. gettime ();

I = 0;
VaR p1start = new date ();
For (; I <total; I ++ ){
If (/* test statement */);
}
P1timespan = new date (). gettime ()-p1start. gettime ();

Connection 1: 32 bytes, ehr... 9, ehr... 7 !!! To know if your browser is ie -- http://webreflection.blogspot.com/2009/01/32-bytes-to-know-if-your-browser-is-ie.html (Wall flip required)
Link 2: Escape Character _ Baidu encyclopedia -- http://baike.baidu.com/view/73.html
Connection 3: javascript conversions-http://www.cnblogs.com/dreampuf/archive/2009/01/22/1380075.html