js the splice and delete

For example, an array is: var textArr = [ 'a', 'b', 'c', 'd'];

Then I want to delete this b element in the array:

Method one: delete delete array

delete textArr[1]  结果为： ["a",undefined,"c","d"]  

Just deleted element becomes undefined keys or other elements unchanged.

Method Two: splice delete array

splice(index,len,[item])   

Note: This method changes the original array.

index: Array index began       

: len length of the replacement / deletion      

item: replacement value, item deletion of empty words

textArr.splice (1,1); the result is: [ "a", "c", "d"] deleted directly change the value of the array of the array.

Detail