The difference between alert() and console.log() in javascript
[1]alert()
[1.1] It has a blocking effect. If you don’t click OK, subsequent code cannot continue to execute
[1.2] alert() can only output string. If alert The output is that the object will automatically call the toString() method
e.g. alert([1,2,3]);//'1,2,3'
[1.3]alert is not supported When writing multiple parameters, only the first value can be output
e.g. alert(1,2,3);//1
[2]console.log()
[2.1]Output on the print station
[2.2]You can print any type of data
e.g. console.log([1,2,3]);//[1,2 ,3]
[2.3]Support multiple parameter writing methods
e.g. console.log(1,2,3)// 1 2 3
alert and console. The result of log is different?
score = [1,2,3];
sortedScore = [];
console.log(score);
sortedScore = score.sort(sortNumber)
console.log(sortedScore);
function sortNumber(a, b) {
return b - a;
}The above output:
[3, 2, 1]
[3, 2, 1]
But change it to alert:
score = [1,2,3];
sortedScore = [];
alert(score);
sortedScore = score.sort(sortNumber)
alert(sortedScore);
function sortNumber(a, b) {
return b - a;
}The above output:
1, 2, 3
3, 2, 1
Why is this happening? Shouldn't they all be:
1, 2, 3
3, 2, 1
?
After some research, I found that it was a problem with chrome implementation. I made inappropriate optimizations for the output and postponed the actual execution of console.log, which is equivalent to "lazy" evaluation. When encountering arrays and objects, this The reference type causes the above problem.
https://bugs.webkit.org/show_bug.cgi?id=35801
This is a very historical BUG, which was fixed in the development version last month .
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