javascript操作cookie的代码详解编程语言

function getCookie( name ) { 
    var start = document.cookie.indexOf( name + "=" ); 
    var len = start + name.length + 1; 
    if ( ( !start ) && ( name != document.cookie.substring( 0, name.length ) ) ) { 
        return null; 
    } 
    if(start == -1) return null; 
    var end = document.cookie.indexOf( ";", len ); 
    if ( end == -1 ) end = document.cookie.length; 
    return unescape( document.cookie.substring( len, end ) ); 
} 
var COOKIE_EXPIRES = 0; 
//expires：以天为单位 
function setCookie( name, value, expires, path, domain, secure) { 
    var today = new Date(); 
    today.setTime( today.getTime() ); 
    if ( expires ) { 
        expires = expires * 1000 * 60 * 60 * 24; 
    }else{ 
        expires = COOKIE_EXPIRES * 1000 * 60 * 60 * 24; 
    } 
    var expires_date = new Date( today.getTime() + (expires) ); 
    document.cookie = name+"="+escape( value ) + 
        ( ( expires ) ? ";expires="+expires_date.toGMTString() : "" ) +  
        ( ( path ) ? ";path=" + (path||'/') :"") + 
        ( ( domain ) ? ";domain=" + (domain||location.hostname) : '') + 
        ( ( secure ) ? ";secure" : "" ); 
} 
 
function deleteCookie( name, path, domain ) { 
    if ( getCookie( name ) ) document.cookie = name + "=" + 
            ( ( path ) ? ";path=" + path : ";path=" + '/') + 
            ( ( domain ) ? ";domain=" + domain : "") + 
            ";expires=Thu, 01-Jan-1970 00:00:01 GMT"; 
}