Call JS function for specific id in HTML

Question

I have below function in JS file name as hello.js inside js folder.

JS

function hello(){
    alert('hello world !);
}

HTML

<!DOCTYPE HTML>
<html>
    <head>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
        <script type="text/javascript" src="js/hello.js"></script>
        <script>
            $(function() {
                $("#hello").hello();
            });
        </script>
    </head>
    <body>
        <button type="button" id="hello">Click Me!</button> 
    </body>
    </html>

How do I attach the hello() function to the button with the id="hello"? I'm doing something wrong but I can't find what.

Edit : I recommend reading all answers for completeness.

Edit2: The purpose of this question was to clarify the general method of attaching functions to specific elements on html. The button and the click interaction was an example.

You are currently trying to call hello as a jQuery extension method. You could write it as a jQuery hello plugin, but just using `click` will do :) — Gone Coding, Jul 23 '15 at 11:53

score 4 · Answer 1 · answered Jul 23 '15 at 11:51

4

You are probably looking to bind click event on button with id hello using hello as handler

$("#hello").click(hello);

answered Jul 23 '15 at 11:51

Adil

143,427
25
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score 3 · Answer 2 · answered Jul 23 '15 at 11:51

3

Use .on() to bind event handler.

$("#hello").on('click', hello);

answered Jul 23 '15 at 11:51

Satpal

129,808
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Why `on` for a simple `click` handler case? Just makes the code longer and no extra gain here. – Gone Coding Jul 23 '15 at 11:54
You very well know `click` is just shorthand for `.on( "click", handler )`. So why not tell OP the use of `.on()` – Satpal Jul 23 '15 at 11:59
because, as I said, *it is longer* (6 characters longer to be precise)... One of the aims for JS code is conciseness :P – Gone Coding Jul 23 '15 at 12:01

score 3 · Accepted Answer · edited May 23 '17 at 12:25

There are many ways to handle events with HTML or DOM.

Defining it in HTML

<button type="button" id="hello" onclick="hello();">Click Me!</button>

Using JQuery

$("#hello").click(hello);

Attaching a function to the event handler using Javascript:

var el = document.getElementById("hello");
    if (el.addEventListener)
        el.addEventListener("click", hello, false);
    else if (el.attachEvent)
        el.attachEvent('onclick', hello);

function hello(){
            alert("inside hello function");
}

Useful links

MDN - onclick event

SO - Ans 1

SO - Ans 2

3pic · Answer 4 · 2015-07-23T12:19:48.113

1

Pure javascript:

var elm=document.getElementById("hello");
elm.onclick= function{ hello();};

Jquery:

$("#hello").click(hello() );

edited Jul 23 '15 at 12:19

answered Jul 23 '15 at 11:56

3pic

1,200
8
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2

well, `on` is not a native javascript function, and in both examples, function `hello` is called , not passed as parameter. – Hacketo Jul 23 '15 at 12:02
Not sure why this answer has *any* upvotes as *it will not work as written*. Please correct your example :) – Gone Coding Jul 23 '15 at 12:17

Call JS function for specific id in HTML

4 Answers4