Get cookie value using javascript

We can use the following function to get a cookie value from dom document.cookie using javascript:

function getCookie( check_name ) {
var a_all_cookies = document.cookie.split( ';' );
var a_temp_cookie = '';
var cookie_name = '';
var cookie_value = '';
var b_cookie_found = false;

for ( i = 0; i <>
a_temp_cookie = a_all_cookies[i].split( '=' );
cookie_name = a_temp_cookie[0].replace(/^\s+|\s+$/g, '');
if ( cookie_name == check_name ){
b_cookie_found = true;
if ( a_temp_cookie.length > 1 ){
cookie_value = unescape( a_temp_cookie[1].replace(/^\s+|\s+$/g, '') );
}
return cookie_value;
break;
}
a_temp_cookie = null;
cookie_name = '';
}
if ( !b_cookie_found ){
return null;
}
}//getCookie