jquery - call function in external js file - javascript

If I have this code in a file called custom.js:
var kennel = function(){this._init();};
kennel.prototype = {
_init: function() {
this.setListeners();
},
setListeners: function(){
...
},
getCats: function(){
alert("Get cats");
}
};
How do I call getCats() from some arbitrary html file?

First of all you would include the javascript by using the <script> tag, generally in the <head>, then after that you can create another <script> tag which you can place your own javascript code in that is specific to the page, and which uses the functionality made available by the included file. For example:
<head>
<script type="text/javascript" src="path/to/custom.js"></script>
<script type="text/javascript">
var myKennel = new kennel();
myKennel.getCats(); // alerts "Get cats"
</script>
</head>
Also, the code you have posted has nothing to do with jQuery - it is plain old, vanilla javascript.

This should be enough:
<script>
var k = new kennel();
k.getCats();
</script>
Here's a sample of it working: http://jsfiddle.net/NHaBb/
​

Related

implementation of global variables in an HTML document with Javascript tags of different types

The situation : I use a script (a) in an HTML document to be able to use a particular SDK. Then I use a second script (b) basic to be able to create a Kendo UI table.
My problem : I try to pass data from script (a) to script (b) via global variables but it doesn't work, what can I do?
Info that might help you:
my document is a form framed by tags
I use Camunda. The first script allows me to use the SDK to retrieve the ID of the instance associated with the form being processed. (but I don't think this is the crux of the problem)
I assume that both scripts are read at the same time by the browser, and that's why script (b) can't read the variable simply because it is not yet created in script (a).
The code :
<script type="text/javascript" src="http://localhost:8080/camunda/app/tasklist/scripts/kendo.all.min.js"></script>
<script cam-script type="text/form-script">
var taskService = camForm.client.resource('task');
var processInstanceId = null;
var result = null;
taskService.get(camForm.taskId, function(err, task) {
//alert(JSON.stringify(task));
debugger;
processInstanceId = task.processInstanceId;
$.get("http://localhost:8080/engine-rest/process-instance/"+processInstanceId+"/variables", function(result) {
debugger;
window.alert("coucou");
console.log(result.JsonWeightSetpoints.value);
});
debugger;
console.log(result.JsonWeightSetpoints.value);
debugger;
});
</script>
<script type="text/javascript">
console.log(result.JsonWeightSetpoints.value);
//this is where I implement the Kendo UI grid
</script>
<div id="grid"></div>
I cannot read the content of the result variable in script (b) because it is not defined.
How do I do this?
Custom events solution:
<script type="text/javascript" src="http://localhost:8080/camunda/app/tasklist/scripts/kendo.all.min.js"></script>
<script cam-script type="text/javascript">
var taskService = camForm.client.resource('task');
var processInstanceId = null;
var result = null;
taskService.get(camForm.taskId, function(err, task) {
//alert(JSON.stringify(task));
debugger;
processInstanceId = task.processInstanceId;
$.get("http://localhost:8080/engine-rest/process-instance/"+processInstanceId+"/variables", function(result) {
debugger;
window.alert("coucou");
console.log(result.JsonWeightSetpoints.value);
// the value is available here, we now can trigger an event and send it
document.dispatchEvent(new CustomEvent("handler", {
detail: { value: result.JsonWeightSetpoints.value }
}));
});
debugger;
console.log(result.JsonWeightSetpoints.value);
debugger;
});
</script>
<script type="text/javascript">
console.log(result.JsonWeightSetpoints.value);
//this is where I implement the Kendo UI grid
// event listener, this would get executed only when we want
document.addEventListener("handler", function(event) {
// write you logic here
console.log(event.detail.value);
});
</script>
<div id="grid"></div>
useful resources:
MDN: Creating and triggering
events
Introducing asynchronous JavaScript

how to create a js function and use it on another files [duplicate]

I wanted to call a function defined in a first.js file in second.js file. Both files are defined in an HTML file like:
<script type="text/javascript" src="first.js"></script>
<script type="text/javascript" src="second.js"></script>
I want to call fn1() defined in first.js in second.js. From my searches answers were if first.js is defined first it is possible, but from my tests I haven't found any way to do that.
Here is my code:
second.js
document.getElementById("btn").onclick = function() {
fn1();
}
first.js
function fn1() {
alert("external fn clicked");
}
A function cannot be called unless it was defined in the same file or one loaded before the attempt to call it.
A function cannot be called unless it is in the same or greater scope then the one trying to call it.
You declare function fn1 in first.js, and then in second you can just have fn1();
1.js:
function fn1 () {
alert();
}
2.js:
fn1();
index.html :
<script type="text/javascript" src="1.js"></script>
<script type="text/javascript" src="2.js"></script>
You could consider using the es6 import export syntax. In file 1;
export function f1() {...}
And then in file 2;
import { f1 } from "./file1.js";
f1();
Please note that this only works if you're using <script src="./file2.js" type="module">
You will not need two script tags if you do it this way. You simply need the main script, and you can import all your other stuff there.
1st JS:
function fn(){
alert("Hello! Uncle Namaste...Chalo Kaaam ki Baat p Aate h...");
}
2nd JS:
$.getscript("url or name of 1st Js File",function(){
fn();
});
You can make the function a global variable in first.js
and have a look at closure and do not put it in document.ready put it outside
you can use ajax too
$.ajax({
url: "url to script",
dataType: "script",
success: success
});
same way you can use jquery getScript
$.getScript( "ajax/test.js" )
.done(function( script, textStatus ) {
console.log( textStatus );
})
.fail(function( jqxhr, settings, exception ) {
$( "div.log" ).text( "Triggered ajaxError handler." );
});
declare function in global scope with window
first.js
window.fn1 = function fn1() {
alert("external fn clicked");
}
second.js
document.getElementById("btn").onclick = function() {
fn1();
}
include like this
<script type="text/javascript" src="first.js"></script>
<script type="text/javascript" src="second.js"></script>
use "var" while creating a function, then you can access that from another file. make sure both files are well connected to your project and can access each other.
file_1.js
var firstLetterUppercase = function(str) {
str = str.toLowerCase().replace(/\b[a-z]/g, function(letter) {
return letter.toUpperCase();
});
return str;
}
accessing this function/variable from file_2.js file
firstLetterUppercase("gobinda");
output => Gobinda
It should work like this:
1.js
function fn1() {
document.getElementById("result").innerHTML += "fn1 gets called";
}
2.js
function clickedTheButton() {
fn1();
}
index.html
<html>
<head>
</head>
<body>
<button onclick="clickedTheButton()">Click me</button>
<script type="text/javascript" src="1.js"></script>
<script type="text/javascript" src="2.js"></script>
</body>
</html>
output
Try this CodePen snippet: link .
Please note this only works if the
<script>
tags are in the body and NOT in the head.
So
<head>
...
<script type="text/javascript" src="first.js"></script>
<script type="text/javascript" src="second.js"></script>
</head>
=> unknown function fn1()
Fails and
<body>
...
<script type="text/javascript" src="first.js"></script>
<script type="text/javascript" src="second.js"></script>
</body>
works.
This is actually coming very late, but I thought I should share,
in index.html
<script type="text/javascript" src="1.js"></script>
<script type="text/javascript" src="2.js"></script>
in 1.js
fn1 = function() {
alert("external fn clicked");
}
in 2.js
fn1()
Use cache if your server allows it to improve speed.
var extern =(url)=> { // load extern javascript
let scr = $.extend({}, {
dataType: 'script',
cache: true,
url: url
});
return $.ajax(scr);
}
function ext(file, func) {
extern(file).done(func); // calls a function from an extern javascript file
}
And then use it like this:
ext('somefile.js',()=>
myFunc(args)
);
Optionally, make a prototype of it to have it more flexible. So that you don't have to define the file every time, if you call a function or if you want to fetch code from multiple files.
first.js
function first() { alert("first"); }
Second.js
var imported = document.createElement("script");
imported.src = "other js/first.js"; //saved in "other js" folder
document.getElementsByTagName("head")[0].appendChild(imported);
function second() { alert("Second");}
index.html
<HTML>
<HEAD>
<SCRIPT SRC="second.js"></SCRIPT>
</HEAD>
<BODY>
method in second js<br/>
method in firstjs ("included" by the first)
</BODY>
</HTML>
window.onload = function(){
document.getElementById("btn").onclick = function(){
fn1();
}
// this should work, It calls when all js files loaded, No matter what position you have written
});
// module.js
export function hello() {
return "Hello";
}
// main.js
import {hello} from 'module'; // or './module'
let val = hello(); // val is "Hello";
reference from https://hype.codes/how-include-js-file-another-js-file
My idea is let two JavaScript call function through DOM.
The way to do it is simple ...
We just need to define hidden js_ipc html tag.
After the callee register click from the hidden js_ipc tag, then
The caller can dispatch the click event to trigger callee.
And the argument is save in the event that you want to pass.
When we need to use above way ?
Sometime, the two javascript code is very complicated to integrate and so many async code there. And different code use different framework but you still need to have a simple way to integrate them together.
So, in that case, it is not easy to do it.
In my project's implementation, I meet this case and it is very complicated to integrate. And finally I found out that we can let two javascript call each other through DOM.
I demonstrate this way in this git code. you can get it through this way. (Or read it from https://github.com/milochen0418/javascript-ipc-demo)
git clone https://github.com/milochen0418/javascript-ipc-demo
cd javascript-ipc-demo
git checkout 5f75d44530b4145ca2b06105c6aac28b764f066e
Anywhere, Here, I try to explain by the following simple case. I hope that this way can help you to integrate two different javascript code easier than before there is no any JavaScript library to support communication between two javascript file that made by different team.
<html>
<head>
<link rel="stylesheet" type="text/css" href="css/style.css" />
</head>
<body>
<div id="js_ipc" style="display:none;"></div>
<div id="test_btn" class="btn">
<a><p>click to test</p></a>
</div>
</body>
<script src="js/callee.js"></script>
<script src="js/caller.js"></script>
</html>
And the code
css/style.css
.btn {
background-color:grey;
cursor:pointer;
display:inline-block;
}
js/caller.js
function caller_add_of_ipc(num1, num2) {
var e = new Event("click");
e.arguments = arguments;
document.getElementById("js_ipc").dispatchEvent(e);
}
document.getElementById("test_btn").addEventListener('click', function(e) {
console.log("click to invoke caller of IPC");
caller_add_of_ipc(33, 22);
});
js/callee.js
document.getElementById("js_ipc").addEventListener('click', (e)=>{
callee_add_of_ipc(e.arguments);
});
function callee_add_of_ipc(arguments) {
let num1 = arguments[0];
let num2 = arguments[1];
console.log("This is callee of IPC -- inner-communication process");
console.log( "num1 + num2 = " + (num1 + num2));
}
better late than never
(function (window) {const helper = { fetchApi: function () { return "oke"}
if (typeof define === 'function' && define.amd) {
define(function () { return helper; });
}
else if (typeof module === 'object' && module.exports) {
module.exports = helper;
}
else {
window.helper = helper;
}
}(window))
index html
<script src="helper.js"></script>
<script src="test.js"></script>
in test.js file
helper.fetchApi()
I have had same problem. I have had defined functions inside jquery document ready function.
$(document).ready(function() {
function xyz()
{
//some code
}
});
And this function xyz() I have called in another file. This doesn't working :) You have to defined function above document ready.
TLDR: Load Global Function Files first, Then Load Event Handlers
Whenever you are accessing an element within a JS file or <script> block, it is essential to check to make sure that element exists, i.e., jQuery's $(document).ready() or plain JS's document.addEventListener('DOMContentLoaded', function(event)....
However, the accepted solution does NOT work in the event that you add an event listener for the DOMContentLoaded, which you can easily observe from the comments.
Procedure for Loading Global Function Files First
The solution is as follows:
Separate the logic of your JS script files so that each file only contains event listeners or global, independent functions.
Load the JS script files with the global, independent functions first.
Load the JS script files with event listeners second. Unlike the other previous files, make sure to wrap your code in document.addEventListener('DOMContentLoaded', function(event) {...}). or document.Ready().

javascript function that uses jquery isn't being called

I'm woking on a ASP.NET project and im trying to use the attr function,
when im putting in the script tag the src for the jquery file the function isnt being called when im calling it via c# code.
<script type ="text/javascript" src="jquery-3.1.1.min.js">
$(document).ready(function () {
function startGame(path) {
alert(path);
$("#test").attr("style", "color:Blue");
$("#game_param").attr("value", path);
$("#game_embed").attr("src", path);
}
});
</script>
I tried to write a simple javascript fucntion
<script type ="text/javascript" src="jquery-3.1.1.min.js">
function startGame(a) {
alert(a);
}
</script>
and it wasn't called either
im getting en error that startGame isn't defined, in both cases.
can someone expain to me what im doing wrong?
You need to include the jQuery source separately from your custom code. Otherwise I believe what is inside of the script tag is ignored.
<script type ="text/javascript" src="jquery-3.1.1.min.js"></script>
<script type="text/javascript">
$(document).ready(function () {
var p = 'here/is/my/path';
function startGame(path) {
alert(path);
$("#test").attr("style", "color:Blue");
$("#game_param").attr("value", path);
$("#game_embed").attr("src", path);
}
startGame(p);
});
</script>
Your Javascript isn't correct.
When you do:
<script type ="text/javascript" src="jquery-3.1.1.min.js">
function startGame(a) {
alert(a);
}
</script>
You're setting the source of the JavaScript file to be the jQuery JS file. If you want to define your own functions, you have to put it in its own script tag, like so:
<script type ="text/javascript" src="jquery-3.1.1.min.js"></script>
<script type="text/javascript">
function startGame(a) {
alert(a);
}
</script>
You actually have multiple errors.
Browsers will ignore any javascript written inside a script tag that has a src attribute. So you need to include jQuery separately, like so:
<script type ="text/javascript" src="jquery-3.1.1.min.js"></script>
<script>
// Your code here.
</script>
You're never actually calling the function, only declaring them. If you're only going to use this once, you don't even need a function:
<script type ="text/javascript" src="jquery-3.1.1.min.js"></script>
<script>
$(document).ready(function () {
alert(path);
$("#test").attr("style", "color:Blue");
$("#game_param").attr("value", path);
$("#game_embed").attr("src", path);
});
</script>
Otherwise, you need to call the function after declaring it like so:
$(document).ready(function () {
function startGame(path) {
// Your code
}
startGame();
});
Function Declarations vs Expressions

jQuery and YUI load

I am using jQuery and YUI-3.6.0 in my application. I am using YUI history module. I trie to create a wrapper on YUI history as below. (This is saved in "history-wrapper.js")
var MyHistory;
(function() {
YUI().use('history', function (Y) {
var history = null;
MyHistory = function() {
history = new Y.History();
};
MyHistory.prototype.save= function() {
history.add({
data : "some data"
});
};
MyHistory.prototype.load= function() {
var data = (history.get("data");
//process data
};
});
})();
I am using this wrapper with following lines of code
<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript" src="yui/yui/yui-min.js"></script>
<script type="text/javascript" src="js/history-wrapper.js"></script>
<script type="text/javascript">
var jQ = jQuery.noConflict();
jQ(document).ready(function() {
var history = new MyHistory();
history.save();
});
</script>
I am using same code in two different application.
In one application, everything works fine as Wrapper is loaded first.
In other application it throws "MyHistory is not defined" as "jQ(document).ready" function is called before wrapper is loaded.
I have no idea what causes this behavior. Can anyone help me?
The callback function "function(Y){... where you define MyHistory...}" in the YUI.use() is only executed when the dependendies (history) are loaded.
Then, you have no assurance MyHistory is defined when you try to use your wrapper.
The solution may be you put your JQuery code in the the YUI.use() too. You can make the YUI loader load jquery and the history module, you the no longer need to wrap the Histroy plugin.
I'm not sure it is exactly like this (cannot check it now).
<script type="text/javascript" src="yui/yui/yui-min.js"></script>
YUI({
modules: {
'jquery': {
path: 'js/jquery.js'
}
}
}).use('history', 'jquery' , function (Y) {
var jQ = Y.jQuery.noConflict(); //or juste jQuery.noConflict();
jQ(document).ready(function() { //it is likely the document will already be ready
var history = new Y.History();
history.save();
});
});

Js javascript code problem

Hi i have a problem with my js code. So, i include in 'head' in my site, script
var Engine;
jQuery
(
function($)
{
Engine =
{
utils :
{
site : function(id)
{
$('#content').html('<strong>Please wait..</strong>').load('engine.php',{'site':id},function()
{
os = {adres:'drugi'};
history.pushState(os,'s',ts);
}
);
},
topnav : function()
{
$('div li').bind('click',function()
{
Engine.utils.site($(this).attr('rel'));
unbind('click',false);
}
);
}
}
};
Engine.utils.topnav();
}
);
Now i want call included script in index.php
<script language="JavaScript" type="text/javascript">
Engine.utils.site(1);
</script>
And here is a problem above code doesn't works.
But if i click on any 'li' element Engine.utils.site work's correctly.
Please help me i try fix it a few days.
Sory for my bad english
Have you tried putting the call in a ready function?
<script language="JavaScript" type="text/javascript">
$(function() {
Engine.utils.site(1);
});
</script>
This happens because of closure. Your object Engine is not visible outside anonymous function

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