// image preload
//source: http://www.trap17.com/index.php/image-preloader-progress-bar-status_t21316.html

function ImagePreload( p_aImages, p_pfnPercent, p_pfnFinished ) {
    // Call-back routines
    this.m_pfnPercent = p_pfnPercent;
    this.m_pfnFinished = p_pfnFinished;

    // Class Member Vars
    this.m_nLoaded = 0;
    this.m_nProcessed = 0;
    this.m_aImages = new Array;
    this.m_nICount = p_aImages.length;

    // Preload Array of Images
    for( var i = 0; i < p_aImages.length; i++ )
        this.Preload( p_aImages[i] );
}

ImagePreload.prototype.Preload = function( p_oImage ) {
    var oImage = new Image;
    this.m_aImages.push( oImage );

    oImage.onload = ImagePreload.prototype.OnLoad;
    oImage.onerror = ImagePreload.prototype.OnError;
    oImage.onabort = ImagePreload.prototype.OnAbort;

    oImage.oImagePreload = this;
    oImage.bLoaded = false;
    oImage.source = p_oImage;
    oImage.src = p_oImage;
}

ImagePreload.prototype.OnComplete = function() {
    this.m_nProcessed++;
    if ( this.m_nProcessed == this.m_nICount )
        this.m_pfnFinished();
    else
        this.m_pfnPercent( Math.round( (this.m_nProcessed / this.m_nICount) * 10 ) );
}

ImagePreload.prototype.OnLoad = function() {
    // 'this' pointer points to oImage Object
    this.bLoaded = true;
    this.oImagePreload.m_nLoaded++;
    this.oImagePreload.OnComplete();
}

ImagePreload.prototype.OnError = function() {
    // 'this' pointer points to oImage Object
    this.bError = true;
    this.oImagePreload.OnComplete();
}

ImagePreload.prototype.OnAbort = function() {
    // 'this' pointer points to oImage Object
    this.bAbort = true;
    this.oImagePreload.OnComplete();
}