get cookie with javascript

gistfile1.js

// Cookie取得
// key:Cookie key
// return: Cookie value. if not found, false.
function getCookie(key){
    if(key){
        var cookieData = document.cookie + ";";
        var startPoint1 = cookieData.indexOf(key);
        var startPoint2 = cookieData.indexOf("=",startPoint1)+1;
        var endPoint = cookieData.indexOf(";",startPoint1);
        if(startPoint2 < endPoint && startPoint1 > -1){
            cookieData = cookieData.substring(startPoint2,endPoint);
            cookieData = cookieData;
            return cookieData;
        }
    }
    return false;
};