How do I pass local variable value from one function to another?

Question

In my script I have 2 functions. First function references to a div element, creates a paragraph element inside div and appends some text to this paragraph element; In my second function is triggered by onclick event attached to a link element. I want the text in the div to be changed to another text when clicking on the link. I do realize that there are 2 options how to achieve this:

1) declare global variables and use them in my second function; 2) pass the variable value from first function to the second function and manipulkate this value from the second function

But the question is how to do I correctly pass the variable value from first function to second function:

Here is the code:

<a href=''onclick='change();return false;'>Change</a>
<div id='box'></div>

Javascript:

window.onload= function createEl(){
    var el = document.createElement('p');
    var x = document.getElementById('box');
    var text = 'text';

    el.appendChild(document.createTextNode(text));
    x.appendChild(el);
}

function change(){
    x.innerHTML="other text";
}

p0rter · Accepted Answer · 2012-05-14 13:54:49Z

1

in general you can write this:

function one(){
   var var1 = "hello";
   two(var1);
}

function two(x){
   alert(x);
}

this will alert "hello".

answered May 14, 2012 at 13:54

p0rter

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Comments

Snuffleupagus · Accepted Answer · 2012-05-14 14:05:44Z

For what you're doing, I would register my events through code to make it easier to pass a variable. We want to use an argument in the event handling function to pass the data to it.

window.onload = function()
{
    // do your normal stuff with creating elements
    var anc = document.getElementById('ID of your a element here');
    if(anc.attachEvent)
    {
        //code for ancient IE
        anc.attachEvent('onclick', function(){change(x);});
    }
    else if(anc.addEventListener)
    {
        //code for modern browsers
        anc.addEventListener('click', function(){change(x);});
    }
}
function change(elem)
{
    elem.innerHTML='other text';
}

Do note that older versions of IE don't recognize addEventListener and use attachEvent instead, as seen in the above if block. Here's the documentation for addEventListener.

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