NSURLProtocol & JavaScript

* Most of the dynamic method to load js can be detect

* Once a js is loaded, the urlprotocal will not detect it any more. But the script will be run once more. Even if the script is altered, the web page won't load it any more.

* Take capture will not trigger url protocol

* Take photo: 

native_urI will return the photo lib's path such as: "assets-library:\/\/asset\/asset.PNG?id=195E78F1-50CA-42A0-8D3E-D93171A61657&ext=PNG"

<!--?xml version="1.0" encoding="UTF-8" standalone="no"?-->

file_url will save to tempory dir, will trigger the urlprotocol, data_uri will return base64 data, will not trigger url protocol.

//************************************************************************************

Most of the time, Firefox, Safari and Opera work without much effort and differences between the 3. However, throw IE into the mix and you’re in a whole different world.This is helpful if you need to dynamically inject javascript.And, the biggest problem was setting a function that you want executed after the script is loaded.By this article I will provide 4 way to dynamically load external JavaScript.

 

choice 1. Using document.write

1	// you need to put an escape character before the closing </script> tag, like this: <\/script>

2	<script language="javascript">

3	document.write("<script src='other.js'><\/script>");

4

</script>

Can be detected;

choice 2.Dynamically change the src property value

1	<script src='' id="s1"></script>

2	<script language="javascript">

3	document.getElementById("s1").src="other.js"

4

</script>

Failed to load script without any error, not detect it

choice 3.Dynamically create <script> element

1

<script>

2	var oHead = document.getElementsByTagName('HEAD').item(0);

3	var oScript= document.createElement("script");

4	oScript.type = "text/javascript";

5	oScript.src="other.js";

6	oHead.appendChild( oScript);

7

</script>

Can be detected;

choice 4. Get JavaScript by using XMLHTTP,then create script object

1	<script language="JavaScript">

2	function GetHttpRequest()

3

{

4	if ( window.XMLHttpRequest ) // Gecko

5	return new XMLHttpRequest() ;

6	else if ( window.ActiveXObject ) // IE

7	return new ActiveXObject("MsXml2.XmlHttp") ;

8

}

9	function AjaxPage(sId, url){

10	var oXmlHttp = GetHttpRequest() ;

11	oXmlHttp.OnReadyStateChange = function()

12

{

13	if ( oXmlHttp.readyState == 4 )

14

{

15	if ( oXmlHttp.status == 200 || oXmlHttp.status == 304 )

16

{

17	IncludeJS( sId, url, oXmlHttp.responseText );

18

}

19

else

20

{

21	alert( 'XML request error: ' + oXmlHttp.statusText + ' (' + oXmlHttp.status + ')' ) ;

22

}

23

}

24

}

25	oXmlHttp.open('GET', url, true);

26	oXmlHttp.send(null);

27

}

28	function IncludeJS(sId, fileUrl, source)

29

{

30	if ( ( source != null ) && ( !document.getElementById( sId ) ) ){

31	var oHead = document.getElementsByTagName('HEAD').item(0);

32	var oScript = document.createElement( "script" );

33	oScript.language = "javascript";

34	oScript.type = "text/javascript";

35	oScript.id = sId;

36	oScript.defer = true;

37	oScript.text = source;

38	oHead.appendChild( oScript );

39

}

40

}

41	AjaxPage( "scrA", "b.js" );

42	alert( "dynamically load javascript");

43	alert( "dynamically load a.js and get the variable：" + str );

44

</script>

 

 

function loadScript(url, callback) {

        var script = document.createElement("script")
        script.type = "text/javascript";

        if (script.readyState) { //IE
            script.onreadystatechange = function () {
                if (script.readyState == "loaded" || script.readyState == "complete") {
                    script.onreadystatechange = null;
                    callback();
                }
            };
        } else { //Others
            script.onload = function () {
                callback();
            };
        }

        script.src = url;
        document.getElementsByTagName("head")[0].appendChild(script);
    }

    loadScript("https://ajax.googleapis.com/ajax/libs/jquery/1.6.1/jquery.min.js", function () {})