A simple dynamic loading js and CSS jquery code

  • 2020-03-30 03:47:26
  • OfStack

A simple jquery code for dynamically loading js and CSS, used to load some common js and CSS files through js functions when generating pages.


//how to use the function below: 
//$.include('file/ajaxa.js');$.include('file/ajaxa.css'); 
//or $.includePath = 'file/';$.include(['ajaxa.js','ajaxa.css']);(only if .js and .css files are in the same directory) 
$.extend({ 
includePath: '', 
include: function(file) 
{ 
var files = typeof file == "string" ? [file] : file; 
for (var i = 0; i < files.length; i++) 
{ 
var name = files[i].replace(/^s|s$/g, ""); 
var att = name.split('.'); 
var ext = att[att.length - 1].toLowerCase(); 
var isCSS = ext == "css"; 
var tag = isCSS ? "link" : "script"; 
var attr = isCSS ? " type='text/css' rel='stylesheet' " : " type='text/javascript' "; 
var link = (isCSS ? "href" : "src") + "='" + $.includePath + name + "'"; 
if ($(tag + "[" + link + "]").length == 0) $("head").prepend("<" + tag + attr + link + "></" + tag + ">"); 
} 
} 
}); 
$.include('../js/jquery-ui-1.8.21.custom.min.js'); 
$.include('../css/black-tie/jquery-ui-1.8.21.custom.css');

The language = 'javascript'
2. When the original author wrote js and CSS tags, he used:


document.write("<" + tag + attr + link + "></" + tag + ">");

But after practice, found the document. The write () method will clear all the content in the original page before writing, also is equivalent to cover, so obviously not meet my needs, I need to load the page dynamically to the page of the import in common js and CSS, not clear I had any other content of the page, so check the API, I switched to:


$("head").prepend("<" + tag + attr + link + "></" + tag + ">");

This method, $("head"). Prepend () method is used in < Head> Appends writes to the very front of the label.

Finally, a supplementary method, also implemented through common js, should be easier to understand than the above method:


Dynamically loading external JavaScript and CSS files 

To load a .js or .css file dynamically, in a nutshell, it means using DOM methods to first create a swanky new "SCRIPT" or "LINK" element, assign it the appropriate attributes, and finally, use element.appendChild() to add the element to the desired location within the document tree. It sounds a lot more fancy than it really is. Lets see how it all comes together: 

function loadjscssfile(filename, filetype){ 
if (filetype=="js"){ //if filename is a external JavaScript file 
var fileref=document.createElement('script') 
fileref.setAttribute("type","text/javascript") 
fileref.setAttribute("src", filename) 
} 
else if (filetype=="css"){ //if filename is an external CSS file 
var fileref=document.createElement("link") 
fileref.setAttribute("rel", "stylesheet") 
fileref.setAttribute("type", "text/css") 
fileref.setAttribute("href", filename) 
} 
if (typeof fileref!="undefined") 
document.getElementsByTagName("head")[0].appendChild(fileref) 
} 

loadjscssfile("myscript.js", "js") //dynamically load and add this .js file 
loadjscssfile("javascript.php", "js") //dynamically load "javascript.php" as a JavaScript file 
loadjscssfile("mystyle.css", "css") ////dynamically load and add this .css file


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