Determine if the JS array package contains an element ____JS

To determine if the JS array package contains an element2010-06-21 15:10:21.0 575 people like this article

To determine if an array contains an element, from the principle, is to traverse the entire array, and then to determine whether equality, we build a wheel, name on the cottage PHP array function in_array () View source print?

1	Array.prototype.in_array = function (e)

2

{

3	for (i=0;i<this.length;i++)

4

{

5	if (this[i] = = e)

6	return true;

7

}

8	return false;

9

}

or view source print?

1	Array.prototype.in_array = function (e)

2

{

3	For (i=0;i<this.length && this[i]!=e;i++);

4	Return! (I==this.length);

5

}

Both of these are possible. is actually a form, the writing is not the same. And this is what Daniel wrote. View Source print?

1	Array.prototype.s=string.fromcharcode (2);

2	Array.prototype.in_array=function (e)

3

{

4	var r=new RegExp (this. S+e+this. S);

5	Return (R.test) (this. S+this.join (this. S) +this. S));

6

}

The use method is view source print?

1	var arr=["A", "B"];

2	alert (Arr.in_array ("a"))