Question

The question I have is how to I get multiple instances of a function to run. Here is my function below – A simple fade function. Problem I’m having is that when it is called a second time it abandons the first call. So if a user clicks on a button it will display a message which fades.

If the user clicks on another button the previous fading message just stops at the current opacity level.

?

What is the stopping mechanism? Where did the previous function go?

The function

function newEffects(element, direction, max_time ) 
{
    newEffects.arrayHold = [];
    newEffects.arrayHold[element.id] = 0;

    function next() 
    {
        newEffects.arrayHold[element.id] += 10;
        if ( direction === 'up' )
        {
            element.style.opacity = newEffects.arrayHold[element.id] / max_time;
        }
        else if ( direction === 'down' )
        {
            element.style.opacity = ( max_time - newEffects.arrayHold[element.id] ) / max_time;
        }
        if ( newEffects.arrayHold[element.id] <= max_time ) 
        {
            setTimeout( next, 10 );
        }
    }
    next();
    return true;
};

The Call

newEffects(this.element, 'down', 4000 ); 

Old Object

/**
 *    Effects - causes all elements that are fading to sync. to same opacity level as they share the same elapsed time.
 */

var Effects = function( element ) 
{
    this.element = element;
};

Effects.prototype.fade = function( direction, max_time ) 
{
    Effects.elapsed = 0;
    var persist_element = this.element;
    function next() 
    {
        Effects.elapsed += 10;
        if ( direction === 'up' )
        {
            persist_element.style.opacity = Effects.elapsed / max_time;
        }
        else if ( direction === 'down' )
        {
            persist_element.style.opacity = ( max_time - Effects.elapsed ) / max_time;
        }
        if ( Effects.elapsed <= max_time ) 
    {
            setTimeout( next, 10 );
        }
    }
    next();
    return true;
};

Answer 1

Try this

function newEffects(element, direction, max_time ) 
{
    var mt=max_time;
    var dir=direction; 
    var el=document.getElementById(element);
    var newEffects={};
    newEffects.arrayHold = [];
    newEffects.arrayHold[el.id] = 0;

    function next() 
    {
        newEffects.arrayHold[el.id] += 10;
        if ( dir === 'up' )
        {
            el.style.opacity = newEffects.arrayHold[el.id] / mt;
        }
        else if ( dir === 'down' )
        {
            el.style.opacity = ( mt - newEffects.arrayHold[el.id] ) / mt;
        }
        if ( newEffects.arrayHold[el.id] <= mt ) 
        {
            setTimeout( next, 10 );
        }
    } next();
};

An example is here.

Declare every variable using var keyword inside the parent function to
keep separate instance of each items, this is how clouser works.