Code _ javascript

IE has many easy-to-use methods and is later copied by other browsers, such as the contains method. If element A contains Element B, true is returned; otherwise, false is returned. The only thing that does not support this method is the opposite of IE firefox. To be compatible with IE and FF, we have to use the following methods:

<! Doctype html> <title> dom contains METHOD by SITU zhengmei </title> <meta charset = "UTF-8"/> <meta name = "keywords" content = "dom contains METHOD by SITU zhengmei "/> <meta name =" description "content =" dom contains METHOD by SITU zhengmei "/> <script type =" text/javascript "> if (!! Window. find) {HTMLElement. prototype. contains = function (B) {return this. compareDocumentPosition (B)-19> 0} window. onload = function () {var A = document. getElementById ('parent'), B = document. getElementById ('child '); alert (. contains (B); alert (B. contains ());} script contains method <p id = "parent"> <p> <strong id = "child"> contains method </strong> </p>
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However, Firefox supports the compareDocumentPosition () method, which is developed by W3C and supported by standard browsers. However, it is not practical, so no one can use it and cannot be promoted. Its usage is similar to that of contains, but the returned value is not a Boolean value, but a very strange value. It is calculated in the following way:

Bits	Number	Meaning
000000	0	Element consistency
000001	1	Node in different documents (or one out of the document)
000010	2	Node B is before node.
000100	4	Node A is before Node B.
001000	8	Node B contains node
010000	16	Node A contains Node B
100000	32	Private Use of browsers

<! Doctype html> <title> dom contains METHOD by SITU zhengmei </title> <meta charset = "UTF-8"/> <meta name = "keywords" content = "dom contains METHOD by SITU <meta name = "description" content = "dom contains METHOD by SITU zhengmei"/> <script type = "text/javascript"> window. onload = function () {var A = document. getElementById ('parent'), B = document. getElementById ('child '); alert (. compareDocumentPosition (B); // B is not connected to A, B is behind A, B is contained by A 4 + 16 = 20 alert (B. compareDocumentPosition (A); // A and B are not connected, A is in front of B, A contains B 2 + 8 = 10} compareDocumentPosition method of script <p id = "parent"> <p> <strong id = "child"> This example is in the standard browser. run. </Strong> </p>
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PPK provides the following solutions.

The Code is as follows:

If (window. Node & Node. prototype &&! Node. prototype. contains ){
Node. prototype. contains = function (arg ){
Return !! (This. compareDocumentPosition (arg) & 16)
}
}

I made a shorter one:

The Code is as follows:

If (!! Window. find ){
HTMLElement. prototype. contains = function (B ){
Return this. compareDocumentPosition (B)-19> 0
}
}

<! Doctype html> <title> dom contains METHOD by SITU zhengmei </title> <meta charset = "UTF-8"/> <meta name = "keywords" content = "dom contains METHOD by SITU zhengmei "/> <meta name =" description "content =" dom contains METHOD by SITU zhengmei "/> <script type =" text/javascript "> if (!! Window. find) {HTMLElement. prototype. contains = function (B) {return this. compareDocumentPosition (B)-19> 0} window. onload = function () {var A = document. getElementById ('parent'), B = document. getElementById ('child '); alert (. contains (B); alert (B. contains ());} script contains method <p id = "parent"> <p> <strong id = "child"> contains method </strong> </p>
[Ctrl + A select all Note: If you need to introduce external Js, You need to refresh it to execute]

The Code is as follows:

// 2011.9.24 by SITU zhengmei
Var contains = function (root, el ){
If (root. compareDocumentPosition)
Return root = el | !! (Root. compareDocumentPosition (el) & 16 );
If (root. contains & amp; el. nodeType = 1 ){
Return root. contains (el) & root! = El;
}
While (el = el. parentNode ))
If (el = root) return true;
Return false;
}