var fontSizeCookieName = "breakingviewscomfontsize";
var fontSizeCookieExpireDate = "31/12/9999 00:00:00";
var defaultFontSize = "72";
var maxFontSize = "102";

function changeFontSize(value)
{
    var currentSize = getBodyFontSizeFromCookie();
    var newValue = parseInt(currentSize)+value;
    if((newValue >= defaultFontSize) && (newValue <= maxFontSize))
    {
        createFontSizeCookie(newValue, fontSizeCookieExpireDate);
        setBodyFontSize();
    }
}

function resetFontSize()
{
    deleteFontSizeCookie();
    setBodyFontSize();
}

function getBodyFontSizeFromCookie()
{
    var fontSize = getFontSizeCookieValue();
    if( ! fontSize)
        return defaultFontSize;
    return fontSize;
}


function setBodyFontSize()
{
    var PercentageSize = getBodyFontSizeFromCookie();
    document.getElementById("mainBody").style.fontSize = PercentageSize + "%";
}

function deleteFontSizeCookie()
{
    createFontSizeCookie('', new Date());
}

function createFontSizeCookie( value, expires )
{
    document.cookie = fontSizeCookieName+"=" + value +"; expires=" + expires + "; path=/";
}

function getFontSizeCookieValue()
{
    var documentCookies = document.cookie;
    var valuePrefix = fontSizeCookieName + "=";
    var startIndex = documentCookies.indexOf("; " + valuePrefix);
    if(startIndex == -1)
    {
        startIndex = documentCookies.indexOf(valuePrefix);
        if( startIndex != 0)
            return null;
    }
    else
        startIndex += 2;
    var endIndex = documentCookies.indexOf(";", startIndex);
    if( endIndex == -1 )
        endIndex = documentCookies.length;
    return unescape(documentCookies.substring(startIndex + valuePrefix.length, endIndex));
}