Shulou(Shulou.com)05/31 Report--

Today, Xiaobian will share with you what the third parameter of setTimeout is and how to use it. The content is detailed and the logic is clear. I believe most people still know too much about this knowledge, so share this article for your reference. I hope you will gain something after reading this article. Let's find out together.

Let's start with a simple code:

setTimeout(function(x) { console.log(x);}, 1000, 1);

Console output 1, then can you continue to add parameters? Let's continue with the following code:

setTimeout(function(x,y) { console.log(x+y);}, 1000, 1, 2);

The console outputs 3, which is obviously the sum of the third and fourth arguments.

See here many small partners should realize, yes, the third parameter of setTimeout is the parameter to the first function of setTimeout.

By querying MDN we can see the description of the third parameter:

var timeoutID = scope.setTimeout(function[, delay, arg1, arg2, ...]); var timeoutID = scope.setTimeout(function[, delay]);var timeoutID = scope.setTimeout(code[, delay]);

Therefore, in fact, setTimeout can have countless parameters, but from the third parameter, it is an optional parameter.

All right, what problem can we solve with this feature? One of the most classic is the use of setTimeout in a for loop.

for(var i = 0; i

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