javascript loadScript asynchronous loading script example explanation_jquery

1. Syntax:
loadScript(url[,callback])
or
loadScript(settings)
2. Parameters supported by settings:
url: script path
async: whether to be asynchronous, default is false (HTML5)
charset: file encoding
cache: whether to cache, default is true
success: function executed after successful loading , execute callback first.
3. Call example:

Copy code The code is as follows:

//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 Jiangzi:
//loadScript(settings[,callback])
loadScript({"url":"http://code.jquery.com/jquery.js","async ”:false,”charset”:”utf-8″},function(){
console.log($)
});

4. Source code :

Copy code The code is as follows:

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()
}
}
}
}