JS Common function Use small memory

The Concat () method is used to concatenate two or more arrays.

The method does not alter the existing array, but only returns a copy of the concatenated array.

var a = [Ocument.write];d (A.concat (4,5));

The shift () method removes the first element from the array and returns the value of the first element.

var New Array (3) arr[0] = "George"arr[1] = "John"arr[2] = "Thomas"+ "<br/>"  + "<br/>") document.write (arr)

The Unshift () method adds one or more elements to the beginning of the array and returns the new length.

var New Array () arr[0] = "George"arr[1] = "John"arr[2] = "Thomas"+ "<br/>") document.write (Arr.unshift ("William") + "<br/>") document.write (arr)

The join () method is used to put all the elements in an array into a string.

The elements are delimited by the specified delimiter. A join can take parameters, including specific separators such as:

var New Array (3) arr[0] = "George"arr[1] = "John"arr[2] = "Thomas"document.write (Arr.join ()) document.write (Arr.join (': '))

The Pop () method is used to delete and return the last element of the array.

<script type= "Text/javascript" >varnew Array (3) arr[0] = "George"arr[1] = " John "arr[2] =" Thomas "document.write (arr) document.write (" <br/> ") document.write ( Arr.pop ()) document.write ("<br/>") document.write (arr)</script>

The push () method adds one or more elements to the end of the array and returns the new length.

var New Array (3) arr[0] = "George"arr[1] = "John"arr[2] = "Thomas"+ "<br/>") document.write (Arr.push ("James") + "<br/>") document.write (arr)

The reverse () method reverses the order of the elements in the array.

<script type= "Text/javascript" >varnew Array (3) arr[0] = "George"arr[1] = " John "arr[2] =" Thomas "+" <br/> ") document.write (Arr.reverse ())</script>

The delete operator removes a reference to a previously defined object property or method.

var New  = "David"; alert (o.name);     // output "David" Delete O.name;alert (o.name);     // output "undefined"