我应该使用for循环结构还是forEach方法进行迭代？

Question

Is one way more efficient? Are there any limitations in one method versus the other? Thanks for any input you guys can give me ;-)

Answer 1

The Array.prototype.forEach method is part of the ECMAScript 5th Edition Specification, is available on all browsers but not in IE.

I would suggest you to use a simple sequential for loop, IMO is more efficient since forEach needs a callback function, a function will be created starting a closure and you don't need to care about IE.

But if you want to use forEach and all the other new Array.prototype methods such as map , filter , every , some , etc... you can add an implementation for IE, in the pages I linked.

Answer 2

Similar to for each but supported in all browsers

for (var i = 0, myArrayElement; myArrayElement = myArray[i]; i++) { 
   //now you can just use 
  // myArrayElement
  // instead of 
  // myArray[i]
}

Just to be aware, I use this when iterating though form collections (ie document.forms[0].elements)