When we need jquery in JavaScript and can't tell if it's loaded, you can automatically judge and load jquery in the following ways:
| The code is as follows |
Copy Code |
| function Getscript (URL, success) {
var script = document.createelement (' script ');
script.src = URL;
var head = document.getElementsByTagName (' head ') [0],
Done = false;
Attach handlers for all browsers
Script.onload = Script.onreadystatechange = function () {
if (!done && (!this.readystate | | | this.readystate = ' loaded ' | | | this.readystate = ' complete ')) {
Done = true;
callback function provided as Param
Success ();
Script.onload = Script.onreadystatechange = null;
Head.removechild (script);
};
};
Head.appendchild (script);
}; if (typeof jQuery = = ' undefined ') {
Alert (' Not found JQuery ');
Getscript (' Http://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js ', function () {
Alert (' jQuery loaded ');
});
} |
loadscript Asynchronous Load Script
First, the grammar:
Loadscript (Url[,callback])
Or
Loadscript (Settings)
Second, the settings supported parameters:
URL: Script Path
Async: Asynchronous, default false (HTML5)
CharSet: File Encoding
Cache: Caching, default to True
Success: A function that executes after the load succeeds, giving priority to executing the callback.
Third, the invocation example:
| The code is as follows |
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Loadscript (Url[,callback])
Loadscript ("Http://code.jquery.com/jquery.js");
Loadscript ("Http://code.jquery.com/jquery.js", function () {
Console.log (1)
});
Loadscript (Settings)
Loadscript ({"url": "Http://code.jquery.com/jquery.js", "async": false, "CharSet": "Utf-8〃," cache ": false});
Loadscript ({"url": "Http://code.jquery.com/jquery.js", "async": false, "CharSet": "Utf-8〃," Success ": function () {
Console.log (2)
}});
Or you can purple:
Loadscript (Settings[,callback])
Loadscript ({"url": "Http://code.jquery.com/jquery.js", "async": false, "CharSet": "Utf-8〃},function () {
Console.log ($)
});
|
Four, the source code:
| The code is as follows |
Copy Code |
| function Loadscript (url,callback) {
var head = Document.head | | document.getElementsByTagName ("Head") [0] | | Document.documentelement,
Script
Options if (typeof url = = = "Object") {
options = URL;
url = undefined;
}
s = Options | | {};
url = URL | | s.url;
Callback = callback | | s.success;
script = document.createelement ("script");
Script.async = S.async | | false;
Script.type = "Text/javascript";
if (s.charset) {
Script.charset = S.charset;
}
if (S.cache = = false) {
URL = url+ (/?/.test (URL)? "&": "?" + "_=" + (new Date ()). GetTime ();
}
script.src = URL;
Head.insertbefore (script, head.firstchild);
if (callback) {
Document.addeventlistener? Script.addeventlistener ("Load", callback, false): Script.onreadystatechange = function () {
if (/loaded|complete/). Test (Script.readystate)) {
Script.onreadystatechange = null
callback ()
}
}
}
} |
