Javascript Cookie读写删除操作的函数

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 ) ); 
} // ---------------------------------------------------- // 
function setCookie( name, value, expires, path, domain, secure ) { 
var today = new Date(); 
today.setTime( today.getTime() ); 
if ( expires ) { 
expires = expires * 1000 * 60 * 60 * 24; 
} 
var expires_date = new Date( today.getTime() + (expires) ); 
document.cookie = name+'='+escape( value ) + 
( ( expires ) ? ';expires='+expires_date.toGMTString() : '' ) + //expires.toGMTString() 
( ( path ) ? ';path=' + path : '' ) + 
( ( domain ) ? ';domain=' + domain : '' ) + 
( ( secure ) ? ';secure' : '' ); 
} 
// ---------------------------------------------------- // 
function deleteCookie( name, path, domain ) 
{ 
if ( getCookie( name ) ) document.cookie = name + '=' + 
( ( path ) ? ';path=' + path : '') + 
( ( domain ) ? ';domain=' + domain : '' ) + 
';expires=Thu, 01-Jan-1970 00:00:01 GMT'; 
}