I am trying to develop a page constructor made all with javascript. The problem comes when I dynamically add 2 scripts on the page that depends on the other. In this example I am loading the jQuery from the CDN, and in the second script I call a jQuery function to modify the text of the title, and, because the first is not already loaded, I get the error ReferenceError: $ is not defined.
What is the best way? Maybe wait to load the next script until previous one gets loaded?
One tip, I dont want to use external libraries like RequireJS (this would need to be updating the page everytime the plugin updates, and it would never be possible in this case).
EXAMPLE
Thats my JS classes:
NS.Script = function(nHasCode, nType, nSrc, nContent){
this.hasCode = nHasCode;
this.src = nSrc;
this.type = nType;
this.content = nContent;
};
NS.Page = function(){
this.id;
this.isIndex;
this.title;
this.metas = [];
this.links = [];
this.styles = [];
this.scripts = [];
this.body;
};
NS.Page.prototype.addScript = function(hasCode, type, src = null, content = null){
var aux = new NS.Script(hasCode, type, src, content);
var pageScripts = this.scripts;
pageScripts.push(aux);
};
NS.Pages = {
load: function(page){
//document.write(page.body);
document.body.innerHTML = page.body;
document.title = page.title;
page.scripts.forEach(function(pageScript) {
if(pageScript.hasCode){
document.write("<script type="+pageScript.type+">"+pageScript.content+"<\/script>");
}else{
var s = document.createElement( 'script' );
s.setAttribute( 'type', pageScript.type );
s.setAttribute( 'src', pageScript.src );
if (s.readyState){ //IE
script.onreadystatechange = function(){
if (s.readyState == "loaded" ||
s.readyState == "complete"){
s.onreadystatechange = null;
//maybe here I have to call the script load of every dependance
}
};
} else { //Others
s.onload = function(){
//callback();
//maybe here I have to call the script load of every dependance
};
}
document.getElementsByTagName("head")[0].appendChild( s );
}
});
}
};
Finally I create a page and add two scripts:
var pagina = NS.Pages.new("Prueba", "Pagina 1");
pagina.title = "Page title";
pagina.isIndex = true;
pagina.body = "<h1 id='title'>Page title with H1</h1><p>This could be a paragraph</p>";
pagina.addScript(false, 'text/javascript', 'https://code.jquery.com/jquery-2.2.3.min.js');
pagina.addScript(true, 'text/javascript', null, "$('#title').text('The new title configured with jQuery');");
NS.Pages.load(pagina);
<script type="text/javascript">
function loadJavaScriptSync(filePath)
{
var req = new XMLHttpRequest();
req.open("GET", filePath, false); // 'false': synchronous.
req.send(null);
var headElement = document.getElementsByTagName("head")[0];
var newScriptElement = document.createElement("script");
newScriptElement.type = "text/javascript";
newScriptElement.text = req.responseText;
headElement.appendChild(newScriptElement);
}
loadJavaScriptSync("file1.js");
loadJavaScriptSync("file2.js");
</script>
Code snippet taken from: http://trevweb.me.uk/javascripthtml-synchronous-and-asynchronous-loading/
Looks like a chicken and egg problem. It stems from the fact that dynamically inserted <script> tags get a default "async" property and are executed in unpredictable order. According to Mozilla, you can request them to be synced:
var s = document.createElement( 'script' );
s.setAttribute( 'type', pageScript.type );
s.setAttribute( 'src', pageScript.src );
s.async = false;
Related
I've got a script that inserts some content into an element using innerHTML.
The content could for example be:
<script type="text/javascript">alert('test');</script>
<strong>test</strong>
Problem is that the code inside the <script> tag doesn't get executed.
I googled it a bit but there were no apparent solutions. If I inserted the content using jQuery $(element).append(content);the script parts got eval'd before being injected into the DOM.
Has anyone got a snippet of code that executes all the <script> elements? The jQuery code was a bit complex so I couldn't really figure out how it was done.
Edit:
By peeking into the jQuery code I've managed to figure out how jQuery does it, which resulted in the following code:
Demo:
<div id="element"></div>
<script type="text/javascript">
function insertAndExecute(id, text)
{
domelement = document.getElementById(id);
domelement.innerHTML = text;
var scripts = [];
ret = domelement.childNodes;
for ( var i = 0; ret[i]; i++ ) {
if ( scripts && nodeName( ret[i], "script" ) && (!ret[i].type || ret[i].type.toLowerCase() === "text/javascript") ) {
scripts.push( ret[i].parentNode ? ret[i].parentNode.removeChild( ret[i] ) : ret[i] );
}
}
for(script in scripts)
{
evalScript(scripts[script]);
}
}
function nodeName( elem, name ) {
return elem.nodeName && elem.nodeName.toUpperCase() === name.toUpperCase();
}
function evalScript( elem ) {
data = ( elem.text || elem.textContent || elem.innerHTML || "" );
var head = document.getElementsByTagName("head")[0] || document.documentElement,
script = document.createElement("script");
script.type = "text/javascript";
script.appendChild( document.createTextNode( data ) );
head.insertBefore( script, head.firstChild );
head.removeChild( script );
if ( elem.parentNode ) {
elem.parentNode.removeChild( elem );
}
}
insertAndExecute("element", "<scri"+"pt type='text/javascript'>document.write('This text should appear as well.')</scr"+"ipt><strong>this text should also be inserted.</strong>");
</script>
Simplified ES6 version of #joshcomley's answer with an example.
No JQuery, No library, No eval, No DOM change, Just pure Javascript.
http://plnkr.co/edit/MMegiu?p=preview
function setInnerHTML(elm, html) {
elm.innerHTML = html;
Array.from(elm.querySelectorAll("script"))
.forEach( oldScriptEl => {
const newScriptEl = document.createElement("script");
Array.from(oldScriptEl.attributes).forEach( attr => {
newScriptEl.setAttribute(attr.name, attr.value)
});
const scriptText = document.createTextNode(oldScriptEl.innerHTML);
newScriptEl.appendChild(scriptText);
oldScriptEl.parentNode.replaceChild(newScriptEl, oldScriptEl);
});
}
Usage
$0.innerHTML = HTML; // does *NOT* run <script> tags in HTML
setInnerHTML($0, HTML); // does run <script> tags in HTML
Here is a very interesting solution to your problem:
http://24ways.org/2005/have-your-dom-and-script-it-too
So it would look like this instead:
<img src="empty.gif" onload="alert('test');this.parentNode.removeChild(this);" />
You should not use the innerHTML property but rather the appendChild method of the Node: a node in a document tree [HTML DOM]. This way you are able to later call your injected code.
Make sure that you understand that node.innerHTML is not the same as node.appendChild. You might want to spend some time on the Javascript Client Reference for more details and the DOM. Hope the following helps...
Sample injection works:
<!DOCTYPE HTML>
<html>
<head>
<title>test</title>
<script language="javascript" type="text/javascript">
function doOnLoad() {
addScript('inject',"function foo(){ alert('injected'); }");
}
function addScript(inject,code) {
var _in = document.getElementById('inject');
var scriptNode = document.createElement('script');
scriptNode.innerHTML = code;
_in.appendChild(scriptNode);
}
</script>
</head>
<body onload="doOnLoad();">
<div id="header">some content</div>
<div id="inject"></div>
<input type="button" onclick="foo(); return false;" value="Test Injected" />
</body>
</html>
The OP's script doesn't work in IE 7. With help from SO, here's a script that does:
exec_body_scripts: function(body_el) {
// Finds and executes scripts in a newly added element's body.
// Needed since innerHTML does not run scripts.
//
// Argument body_el is an element in the dom.
function nodeName(elem, name) {
return elem.nodeName && elem.nodeName.toUpperCase() ===
name.toUpperCase();
};
function evalScript(elem) {
var data = (elem.text || elem.textContent || elem.innerHTML || "" ),
head = document.getElementsByTagName("head")[0] ||
document.documentElement,
script = document.createElement("script");
script.type = "text/javascript";
try {
// doesn't work on ie...
script.appendChild(document.createTextNode(data));
} catch(e) {
// IE has funky script nodes
script.text = data;
}
head.insertBefore(script, head.firstChild);
head.removeChild(script);
};
// main section of function
var scripts = [],
script,
children_nodes = body_el.childNodes,
child,
i;
for (i = 0; children_nodes[i]; i++) {
child = children_nodes[i];
if (nodeName(child, "script" ) &&
(!child.type || child.type.toLowerCase() === "text/javascript")) {
scripts.push(child);
}
}
for (i = 0; scripts[i]; i++) {
script = scripts[i];
if (script.parentNode) {script.parentNode.removeChild(script);}
evalScript(scripts[i]);
}
};
Here's a shorter, more efficient script that also works for scripts with the src property:
function insertAndExecute(id, text) {
document.getElementById(id).innerHTML = text;
var scripts = Array.prototype.slice.call(document.getElementById(id).getElementsByTagName("script"));
for (var i = 0; i < scripts.length; i++) {
if (scripts[i].src != "") {
var tag = document.createElement("script");
tag.src = scripts[i].src;
document.getElementsByTagName("head")[0].appendChild(tag);
}
else {
eval(scripts[i].innerHTML);
}
}
}
Note: whilst eval may cause a security vulnerability if not used properly, it is much faster than creating a script tag on the fly.
Try this snippet:
function stripAndExecuteScript(text) {
var scripts = '';
var cleaned = text.replace(/<script[^>]*>([\s\S]*?)<\/script>/gi, function(){
scripts += arguments[1] + '\n';
return '';
});
if (window.execScript){
window.execScript(scripts);
} else {
var head = document.getElementsByTagName('head')[0];
var scriptElement = document.createElement('script');
scriptElement.setAttribute('type', 'text/javascript');
scriptElement.innerText = scripts;
head.appendChild(scriptElement);
head.removeChild(scriptElement);
}
return cleaned;
};
var scriptString = '<scrip' + 't + type="text/javascript">alert(\'test\');</scr' + 'ipt><strong>test</strong>';
document.getElementById('element').innerHTML = stripAndExecuteScript(scriptString);
function insertHtml(id, html)
{
var ele = document.getElementById(id);
ele.innerHTML = html;
var codes = ele.getElementsByTagName("script");
for(var i=0;i<codes.length;i++)
{
eval(codes[i].text);
}
}
It works in Chrome in my project
A solution without using "eval":
var setInnerHtml = function(elm, html) {
elm.innerHTML = html;
var scripts = elm.getElementsByTagName("script");
// If we don't clone the results then "scripts"
// will actually update live as we insert the new
// tags, and we'll get caught in an endless loop
var scriptsClone = [];
for (var i = 0; i < scripts.length; i++) {
scriptsClone.push(scripts[i]);
}
for (var i = 0; i < scriptsClone.length; i++) {
var currentScript = scriptsClone[i];
var s = document.createElement("script");
// Copy all the attributes from the original script
for (var j = 0; j < currentScript.attributes.length; j++) {
var a = currentScript.attributes[j];
s.setAttribute(a.name, a.value);
}
s.appendChild(document.createTextNode(currentScript.innerHTML));
currentScript.parentNode.replaceChild(s, currentScript);
}
}
This essentially clones the script tag and then replaces the blocked script tag with the newly generated one, thus allowing execution.
scriptNode.innerHTML = code didn't work for IE. The only thing to do is replace with scriptNode.text = code and it work fine
It's easier to use jquery $(parent).html(code) instead of parent.innerHTML = code:
var oldDocumentWrite = document.write;
var oldDocumentWriteln = document.writeln;
try {
document.write = function(code) {
$(parent).append(code);
}
document.writeln = function(code) {
document.write(code + "<br/>");
}
$(parent).html(html);
} finally {
$(window).load(function() {
document.write = oldDocumentWrite
document.writeln = oldDocumentWriteln
})
}
This also works with scripts that use document.write and scripts loaded via src attribute. Unfortunately even this doesn't work with Google AdSense scripts.
Try this, it works for me on Chrome, Safari & Firefox:
var script = document.createElement('script');
script.innerHTML = 'console.log("hi")';
document.body.appendChild(script);
--> logs "hi"
One thing to note though, is that the following div-nested script will NOT run:
var script = document.createElement('div');
script.innerHTML = '<script>console.log("hi")</script>';
document.body.appendChild(script);
--> doesn't log anything
For a script to run it has to be created as a node then appended as a child. You can even append a script inside a previously injected div & it will run (I've run into this before when trying to get ad server code to work):
var div = document.createElement('div');
div.id = 'test-id';
document.body.appendChild(div);
var script = document.createElement('script');
script.innerHTML = 'console.log("hi")';
document.getElementById('test-id').appendChild(script);
--> logs "hi"
Execute script element by normal .innerHTML just don't put "" start and closing tags in .innerhtml value. Have a look on my code, it's just simple as normal code no jQuery or any other long JavaScript function
<h2>Click on Run to execute script</h2>
<button type="button" onclick="run()">Run</button>
<script id="my_script"></script>
<script>
document.getElementById("my_script").innerHTML= "function run(){alert('Wow! Script executed :)');}";
</script>
Extending off of Larry's. I made it recursively search the entire block and children nodes.
The script now will also call external scripts that are specified with src parameter.
Scripts are appended to the head instead of inserted and placed in the order they are found. So specifically order scripts are preserved. And each script is executed synchronously similar to how the browser handles the initial DOM loading. So if you have a script block that calls jQuery from a CDN and than the next script node uses jQuery... No prob! Oh and I tagged the appended scripts with a serialized id based off of what you set in the tag parameter so you can find what was added by this script.
exec_body_scripts: function(body_el, tag) {
// Finds and executes scripts in a newly added element's body.
// Needed since innerHTML does not run scripts.
//
// Argument body_el is an element in the dom.
function nodeName(elem, name) {
return elem.nodeName && elem.nodeName.toUpperCase() ===
name.toUpperCase();
};
function evalScript(elem, id, callback) {
var data = (elem.text || elem.textContent || elem.innerHTML || "" ),
head = document.getElementsByTagName("head")[0] ||
document.documentElement;
var script = document.createElement("script");
script.type = "text/javascript";
if (id != '') {
script.setAttribute('id', id);
}
if (elem.src != '') {
script.src = elem.src;
head.appendChild(script);
// Then bind the event to the callback function.
// There are several events for cross browser compatibility.
script.onreadystatechange = callback;
script.onload = callback;
} else {
try {
// doesn't work on ie...
script.appendChild(document.createTextNode(data));
} catch(e) {
// IE has funky script nodes
script.text = data;
}
head.appendChild(script);
callback();
}
};
function walk_children(node) {
var scripts = [],
script,
children_nodes = node.childNodes,
child,
i;
if (children_nodes === undefined) return;
for (i = 0; i<children_nodes.length; i++) {
child = children_nodes[i];
if (nodeName(child, "script" ) &&
(!child.type || child.type.toLowerCase() === "text/javascript")) {
scripts.push(child);
} else {
var new_scripts = walk_children(child);
for(j=0; j<new_scripts.length; j++) {
scripts.push(new_scripts[j]);
}
}
}
return scripts;
}
var i = 0;
function execute_script(i) {
script = scripts[i];
if (script.parentNode) {script.parentNode.removeChild(script);}
evalScript(scripts[i], tag+"_"+i, function() {
if (i < scripts.length-1) {
execute_script(++i);
}
});
}
// main section of function
if (tag === undefined) tag = 'tmp';
var scripts = walk_children(body_el);
execute_script(i);
}
Just do:
document.body.innerHTML = document.body.innerHTML + '<img src="../images/loaded.gif" alt="" onload="alert(\'test\');this.parentNode.removeChild(this);" />';
Made this new helper function in TypeScript, maybe someone will appreciate it. If you remove type declaration from script parameter it will just be plain JS.
const evalPageScripts = () => {
const scripts = document.querySelectorAll('script');
scripts.forEach((script: HTMLScriptElement) => {
const newScript = document.createElement('script');
newScript.type = 'text/javascript';
newScript.src = script.src;
if (script.parentNode) {
script.parentNode.removeChild(script);
}
return document.body.appendChild(newScript);
})
};
export default evalPageScripts;
Using the short and sweet approach from https://stackoverflow.com/a/62641523/3394495 :
It first parses the HTML to a DocumentFragement (using createContextualFragment which is supported in all modern browsers, yet marked experimental) and then adds that to the DOM.
This will execute inline scripts.
export function setInnerHTMLAndExecuteScripts(element: HTMLElement, html: string) {
const newContent = document.createRange().createContextualFragment(html);
element.innerHTML = '';
element.append(newContent);
}
You may take a look at this post. The code might look like this:
var actualDivToBeUpdated = document.getElementById('test');
var div = document.createElement('div');
div.innerHTML = '<script type="text/javascript">alert("test");<\/script>';
var children = div.childNodes;
actualDivToBeUpdated.innerHTML = '';
for(var i = 0; i < children.length; i++) {
actualDivToBeUpdated.appendChild(children[i]);
}
Thanks to Larry's script, which worked perfectly well in IE10, this is what I've used:
$('#' + id)[0].innerHTML = result;
$('#' + id + " script").each(function() { this.text = this.text || $(this).text();} );
Here is my solution in a recent project.
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Sample</title>
</head>
<body>
<h1 id="hello_world">Sample</h1>
<script type="text/javascript">
var div = document.createElement("div");
var t = document.createElement('template');
t.innerHTML = "Check Console tab for javascript output: Hello world!!!<br/><script type='text/javascript' >console.log('Hello world!!!');<\/script>";
for (var i=0; i < t.content.childNodes.length; i++){
var node = document.importNode(t.content.childNodes[i], true);
div.appendChild(node);
}
document.body.appendChild(div);
</script>
</body>
</html>
Expending the answer of Lambder
document.body.innerHTML = '<img src="../images/loaded.gif" alt="" > onload="alert(\'test\');this.parentNode.removeChild(this);" />';
You can use base64 image to create and load your script
<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAZdEVYdFNvZnR3YXJlAHBhaW50Lm5ldCA0LjAuMjHxIGmVAAAADUlEQVQYV2P4//8/AwAI/AL+iF8G4AAAAABJRU5ErkJggg=="
onload="var script = document.createElement('script'); script.src = './yourCustomScript.js'; parentElement.append(script);" />
Or if you have a Iframe you can use it instead
<iframe src='//your-orginal-page.com' style='width:100%;height:100%'
onload="var script = document.createElement('script'); script.src = './your-coustom-script.js'; parentElement.append(script);"
frameborder='0'></iframe>
I needed something similar, but needed the script to remain or be re-created in the same spot as the original script, since my script targets the location of the script tag in the DOM to create/target elements. I also made the script recursive to make sure it also works if it is more than one level down.
NOTE: I use const here, if you have a older browser, just use var.
window.exec_body_scripts = function(body_el) {
// ref: https://stackoverflow.com/questions/2592092/executing-script-elements-inserted-with-innerhtml based on Larry K's answer
// Finds and executes scripts in a newly added element's body.
// Needed since innerHTML does not run scripts.
//
// Argument body_el is an element in the dom.
const
type__Js = 'text/javascript',
tagName__Script = 'script',
tagName__Script__Upper = tagName__Script.toUpperCase();
var scripts = [], script, i;
function evalScript(elem) {
var parent = elem.parentNode,
data = (elem.text || elem.textContent || elem.innerHTML || ""),
script = document.createElement(tagName__Script);
script.type = type__Js;
try {
// doesn't work on ie...
script.appendChild(document.createTextNode(data));
} catch (e) {
// IE has funky script nodes
script.text = data;
}
// Make sure to re-insert the script at the same position
// to make sure scripts that target their position
// in the DOM function as expected.
var parent = elem.parentNode;
parent.insertBefore(script, elem);
parent.removeChild(elem);
};
// Get all scripts (recursive)
if (typeof (document.querySelectorAll) !== typeof (void 0)) {
document.querySelectorAll('script').forEach((scr) => { if (!scr.type || scr.type.toLowerCase() === type__Js) scripts.push(scr); });
}
else {
var children_nodes = body_el.childNodes, child;
for (i = 0; children_nodes[i]; i++) {
child = children_nodes[i];
if (
child.nodeName
&&
child.nodeName.toUpperCase() === tagName__Script__Upper
&&
(
!child.type
||
child.type.toLowerCase() === type__Js
)
) {
scripts.push(child);
}
// Recursive call
window.exec_body_scripts(child);
}
}
for (i = 0; scripts[i]; i++) {
evalScript(scripts[i]);
}
};
I had also pages that needed to execute javascript code (with eval) after the javascript files are loaded so did put load events on the script createelement so when the javascript file(s) were loaded gets executed. My website is a MVC SPA application. It loads partial pages with ajax. Those partial pages are set with innerhtml and then the javascript files are loaded and the javascript code on thst partial page.
Try function eval().
data.newScript = '<script type="text/javascript">//my script...</script>'
var element = document.getElementById('elementToRefresh');
element.innerHTML = data.newScript;
eval(element.firstChild.innerHTML);
This is a real example from a project that i am developing.
Thanks to this post
It's my js:
const map = new Map();
jsonData.list.forEach(function (item) {
if (!map.get(item.type)) {
usedLaterScript = document.createElement('script');
usedLaterScript.type = 'text/javascript';
usedLaterScript.src = 'js/component/' + item.type + '.js';
document.body.appendChild(usedLaterScript);
map.set(item.type, item.type);
}
});
jsonData:[{"type":"input"},{"type":"radio"},{"type":"select"}]
I want know when all js(like input.js,radio.js,select.js) was loaded,then I can do next
It could take time to load a dynamic added JS file. so you can bind a callback to the script tag like below, I load JQuery dynamically here.
<script>
let usedLaterScript = document.createElement('script');
usedLaterScript.src = 'https://code.jquery.com/jquery-3.3.1.min.js';
document.body.appendChild(usedLaterScript);
usedLaterScript.onload = function() {
if(allScriptsLoaded) {
allScriptsLoaded();
}
};
</script>
<script>
allScriptsLoaded = function() {
console.log("Jquery loaded",$);
}
</script>
I have a code for defer loading of javascript I am wondering if the code will load the scripts in order (JQuery.min first) according to where they are in the code ?
function downloadJSAtOnload() {
var element01 = document.createElement("script");
element01.src = "js/jquery.min.js";
document.body.appendChild(element01);
var element02 = document.createElement("script");
element02.src = "js/plugins.js";
document.body.appendChild(element02);
var element03 = document.createElement("script");
element03.src = "js/scripts.js";
document.body.appendChild(element03);
var element04 = document.createElement("script");
element04.src = "js/SmoothScroll.min.js";
document.body.appendChild(element04);
var element05 = document.createElement("script");
element05.src = "js/contact-form.js";
document.body.appendChild(element05);
}
if (window.addEventListener)
window.addEventListener("load", downloadJSAtOnload, false);
else if (window.attachEvent)
window.attachEvent("onload", downloadJSAtOnload);
else window.onload = downloadJSAtOnload;
If this doesn't load JQuery.min first and then the other js files how can you make JQuery.min the first script to load and then the rest after that has loaded?
Also I am guessing for example the contact-form.js will be one of the first to finish loading as it's small so this could cause the Uncaught ReferenceError: $ is not defined I'm guessing because the JQuery.min hasn't finished downloading so how would you solved this ? I'm guessing an listener / if finished loading load the others else wait...
Thanks in advance
found here Load jQuery with JavaScript using Promises
function loadScript(url) {
return new Promise(function(resolve reject) {
var script = document.createElement("script");
script.onload = resolve;
script.onerror = reject;
script.src = url;
document.getElementsByTagName("head")[0].appendChild(script);
});
}
function loadjQuery() {
if (window.jQuery) {
// already loaded and ready to go
return Promise.resolve();
} else {
return loadScript('https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js');
}
}
// Usage:
loadjQuery().then(function() {
// code here that uses jQuery
}, function() {
// error loading jQuery
});
This is quick, but I think it should work.
function downloadJSAtOnload() {
var element01 = document.createElement("script");
element01.src = "js/jquery.min.js";
document.body.appendChild(element01);
element01.onload = function() {
var element02 = document.createElement("script");
element02.src = "js/plugins.js";
document.body.appendChild(element02);
var element03 = document.createElement("script");
element03.src = "js/scripts.js";
document.body.appendChild(element03);
var element04 = document.createElement("script");
element04.src = "js/SmoothScroll.min.js";
document.body.appendChild(element04);
var element05 = document.createElement("script");
element05.src = "js/contact-form.js";
document.body.appendChild(element05);
}
}
I have this script
<script>
function loadJS(src, callback) {
var s = document.createElement('script');
s.src = src;
s.async = true;
s.onreadystatechange = s.onload = function() {
var state = s.readyState;
if (!callback.done && (!state || /loaded|complete/.test(state))) {
callback.done = true;
callback();
}
};
document.getElementsByTagName('head')[0].appendChild(s);
}
loadJS('/script/script.js', function() {
// put your code here to run after script is loaded
});
</script>
And I can't figure out how can I get response data from the script I'm trying to load.
Basically, this script contains a function that does something and then returns some value.
I know that in jQuery analog in would be just data argument in getScript function, but I only have native JS here.
What and where should I add to get response data in my script?
Assuming that your script contains a function declared in a global scope, you can simply include this script and then execute any function / access any member from this script:
After your script has been loaded and executed, you can work with it just like with a simple script which is a part of your current document.
Here is a demo which loads jQuery script from Google CDN and then outputs jQuery version (which is a part of jQuery library):
function loadJS(src, callback) {
var s = document.createElement('script');
s.src = src;
s.async = true;
s.onreadystatechange = s.onload = function() {
var state = s.readyState;
if (!callback.done && (!state || /loaded|complete/.test(state))) {
callback.done = true;
callback();
}
};
document.getElementsByTagName('head')[0].appendChild(s);
}
console.log("typeof jQuery: " + typeof jQuery); // jQuery not loaded
loadJS("https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js", function() {
console.log("typeof jQuery: " + typeof jQuery + ", version = " + jQuery.fn.jquery); // jQuery has been loaded
});
I want to dynamically include a script tag in a webpage however I have no control of it's src so src="source.js" may look like this.
document.write('<script type="text/javascript">')
document.write('alert("hello world")')
document.write('</script>')
document.write('<p>goodbye world</p>')
Now ordinarily putting
<script type="text/javascript" src="source.js"></script>
In the head works fine but is there any other way I can add source.js dynamically using something like innerHTML?
jsfiddle of what i've tried
var my_awesome_script = document.createElement('script');
my_awesome_script.setAttribute('src','http://example.com/site.js');
document.head.appendChild(my_awesome_script);
You can use the document.createElement() function like this:
function addScript( src ) {
var s = document.createElement( 'script' );
s.setAttribute( 'src', src );
document.body.appendChild( s );
}
There is the onload function, that could be called when the script has loaded successfully:
function addScript( src, callback ) {
var s = document.createElement( 'script' );
s.setAttribute( 'src', src );
s.onload=callback;
document.body.appendChild( s );
}
It's almost a decade later and nobody bothers to write the Promise version, so here is mine (based on this awnser):
function addScript(src) {
return new Promise((resolve, reject) => {
const s = document.createElement('script');
s.setAttribute('src', src);
s.addEventListener('load', resolve);
s.addEventListener('error', reject);
document.body.appendChild(s);
});
}
Usage
try {
await addScript('https://api.stackexchange.com/js/2.0/all.js');
// do something after it was loaded
} catch (e) {
console.log(e);
}
a nice little script I wrote to load multiple scripts:
function scriptLoader(scripts, callback) {
var count = scripts.length;
function urlCallback(url) {
return function () {
console.log(url + ' was loaded (' + --count + ' more scripts remaining).');
if (count < 1) {
callback();
}
};
}
function loadScript(url) {
var s = document.createElement('script');
s.setAttribute('src', url);
s.onload = urlCallback(url);
document.head.appendChild(s);
}
for (var script of scripts) {
loadScript(script);
}
};
usage:
scriptLoader(['a.js','b.js'], function() {
// use code from a.js or b.js
});
When scripts are loaded asynchronously they cannot call document.write. The calls will simply be ignored and a warning will be written to the console.
You can use the following code to load the script dynamically:
var scriptElm = document.createElement('script');
scriptElm.src = 'source.js';
document.body.appendChild(scriptElm);
This approach works well only when your source belongs to a separate file.
But if you have source code as inline functions which you want to load dynamically and want to add other attributes to the script tag, e.g. class, type, etc., then the following snippet would help you:
var scriptElm = document.createElement('script');
scriptElm.setAttribute('class', 'class-name');
var inlineCode = document.createTextNode('alert("hello world")');
scriptElm.appendChild(inlineCode);
document.body.appendChild(scriptElm);
You can try following code snippet.
function addScript(attribute, text, callback) {
var s = document.createElement('script');
for (var attr in attribute) {
s.setAttribute(attr, attribute[attr] ? attribute[attr] : null)
}
s.innerHTML = text;
s.onload = callback;
document.body.appendChild(s);
}
addScript({
src: 'https://www.google.com',
type: 'text/javascript',
async: null
}, '<div>innerHTML</div>', function(){});
A one-liner (no essential difference to the answers above though):
document.body.appendChild(document.createElement('script')).src = 'source.js';
This Is Work For Me.
You Can Check It.
var script_tag = document.createElement('script');
script_tag.setAttribute('src','https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js');
document.head.appendChild(script_tag);
window.onload = function() {
if (window.jQuery) {
// jQuery is loaded
alert("ADD SCRIPT TAG ON HEAD!");
} else {
// jQuery is not loaded
alert("DOESN'T ADD SCRIPT TAG ON HEAD");
}
}
Loads scripts that depends on one another with the right order.
Based on Satyam Pathak response, but fixed the onload.
It was triggered before the script actually loaded.
const scripts = ['https://www.gstatic.com/firebasejs/6.2.0/firebase-storage.js', 'https://www.gstatic.com/firebasejs/6.2.0/firebase-firestore.js', 'https://www.gstatic.com/firebasejs/6.2.0/firebase-app.js']
let count = 0
const recursivelyAddScript = (script, cb) => {
const el = document.createElement('script')
el.src = script
if(count < scripts.length) {
count ++
el.onload = () => recursivelyAddScript(scripts[count])
document.body.appendChild(el)
} else {
console.log('All script loaded')
return
}
}
recursivelyAddScript(scripts[count])
Well, there are multiple ways you can include dynamic javascript,
I use this one for many of the projects.
var script = document.createElement("script")
script.type = "text/javascript";
//Chrome,Firefox, Opera, Safari 3+
script.onload = function(){
console.log("Script is loaded");
};
script.src = "file1.js";
document.getElementsByTagName("head")[0].appendChild(script);
You can call create a universal function which can help you to load as many javascript files as needed. There is a full tutorial about this here.
Inserting Dynamic Javascript the right way
No one mentioned it, but you can also stick the actual source code into a script tag by making a URL out of it using URL and Blob:
const jsCode = `
// JS code in here. Maybe you extracted it from some HTML string.
`
const url = URL.createObjectURL(new Blob([jsCode]))
const script = document.createElement('script')
script.src = url
URL.revokeObjectURL(url) // dispose of it when done
as for the jsCode, you may have gotten it from some HTML.
Here's a more full example of how you'd handle any number of scripts in an HTML source:
main()
async function main() {
const scriptTagOpen = /<script\b[^>]*>/g
const scriptTagClose = /<\/script\b[^>]*>/g
const scriptTagRegex = /<script\b[^>]*>[\s\S]*?<\/script\b[^>]*>/g
const response = await fetch('path/to/some.html')
const html = await response.text()
someElement.innerHTML = html
// We need to get the script tags and manually add them to DOM
// because otherwise innerHTML will not execute them.
const codes =
html
.match(scriptTagRegex)
?.map(code => code.replace(scriptTagOpen, '').replace(scriptTagClose, ''))
.map(code => URL.createObjectURL(new Blob([code]))) || []
for (const code of codes) {
const script = document.createElement('script')
script.src = code
someElement.append(script)
URL.revokeObjectURL(code)
}
}
the only way to do this is to replace document.write with your own function which will append elements to the bottom of your page. It is pretty straight forward with jQuery:
document.write = function(htmlToWrite) {
$(htmlToWrite).appendTo('body');
}
If you have html coming to document.write in chunks like the question example you'll need to buffer the htmlToWrite segments. Maybe something like this:
document.write = (function() {
var buffer = "";
var timer;
return function(htmlPieceToWrite) {
buffer += htmlPieceToWrite;
clearTimeout(timer);
timer = setTimeout(function() {
$(buffer).appendTo('body');
buffer = "";
}, 0)
}
})()
I tried it by recursively appending each script
Note If your scripts are dependent one after other, then position will need to be in sync.
Major Dependency should be in last in array so that initial scripts can use it
const scripts = ['https://www.gstatic.com/firebasejs/6.2.0/firebase-storage.js', 'https://www.gstatic.com/firebasejs/6.2.0/firebase-firestore.js', 'https://www.gstatic.com/firebasejs/6.2.0/firebase-app.js']
let count = 0
const recursivelyAddScript = (script, cb) => {
const el = document.createElement('script')
el.src = script
if(count < scripts.length) {
count ++
el.onload = recursivelyAddScript(scripts[count])
document.body.appendChild(el)
} else {
console.log('All script loaded')
return
}
}
recursivelyAddScript(scripts[count])
Here is a minified snippet, same code as Google Analytics and Facebook Pixel uses:
!function(e,s,t){(t=e.createElement(s)).async=!0,t.src="https://example.com/foo.js",(e=e.getElementsByTagName(s)[0]).parentNode.insertBefore(t,e)}(document,"script");
Replace https://example.com/foo.js with your script path.
window.addEventListener("load", init);
const loadScript = async (url) => {
const response = await fetch(url);
const script = await response.text();
eval(script);
}
function init() {
const wistiaVideo = document.querySelector(".wistia_embed");
if ("IntersectionObserver" in window && "IntersectionObserverEntry" in window && "intersectionRatio" in window.IntersectionObserverEntry.prototype) {
let lazyVideoObserver = new IntersectionObserver(function (entries, observer) {
entries.forEach(function (entry) {
if (entry.isIntersecting) {
setTimeout(() => loadScript("//fast.wistia.com/assets/external/E-v1.js"), 1000);
lazyVideoObserver.unobserve(entry.target);
console.log("E-v1.js script loaded from fast.wistia.com");
}
});
});
lazyVideoObserver.observe(wistiaVideo);
}
}
<div style="height: 150vh; background-color: #f7f7f7;"></div>
<h1>Wistia Video!</h1>
<div class="wistia_embed wistia_async_29b0fbf547" style="width:640px;height:360px;"> </div>
<h1>Video Ended!</h1>