JS设置cookie、读取cookie、删除cookie

// 设置cookie   
function setCookie(c_name, value, expiredays) {                   
    var exdate = new Date();                   
    exdate.setDate(exdate.getDate() + expiredays);                   
    document.cookie = c_name + "=" + escape(value) + ";     
    expires=" + exdate.toGMTString() + ";     
    path=/";         
} 

// 读取cookie   
function getCookie(c_name) {
    if (document.cookie.length > 0)     {
        c_start = document.cookie.indexOf(c_name + "=")           
        if (c_start != -1){ 
            c_start = c_start + c_name.length + 1 
            c_end = document.cookie.indexOf(";", c_start) 
            if (c_end == -1)   
                c_end = document.cookie.length   
                return unescape(document.cookie.substring(c_start, c_end))   
            } 
        } 
    return "" 
}

// 检查cookie 
function checkCookie(c_name) {     
    username = getCookie(c_name);     
    console.log(username);     
    if (username != null && username != "")     
    { return true; }     
    else     
    { return false;  }
}

// 清除cookie 
function clearCookie(name) {     
    setCookie(name, "", -1); 
}