Cookie managing functions

gistfile1.js

// helpers to manipulate cookies. see: http://www.quirksmode.org/js/cookies.html

/**
 * Create a cookie for site
 *
 * @param name         Name for cookie
 * @param value        Value for cookie
 * @param minutes      Number of minutes this cookie will be valid for.
 */
function createCookie(name, value, minutes) {
  if (minutes) {
    var date = new Date();
    date.setTime( date.getTime() + (minutes * 60 * 1000));
    var expires = "; expires=" + date.toGMTString();
  } else {
    var expires = ""; 
  }
  document.cookie = name + "=" + value + expires + "; path=/";
}

/**
 * Retrieve a cookie
 *
 * @param name        Name of cookie
 * @returns           The value stored in the cookie null otherwiste.
 */
function readCookie(name) {
  var nameEQ = name + "=";
  var ca = document.cookie.split(';');

  for(var i = 0; i < ca.length; i++) {

    var c = ca[i];
    while (c.charAt(0) == ' ') {
      c = c.substring(1, c.length);
    }   

    // workaround for a in chrome (old version)
    if ( i == ca.length ) { 
      return null;
    }   

    if ( c.indexOf( nameEQ ) != -1 ) { 
      return c.substring( nameEQ.length, c.length );
    }   
  }
  return null;
}

/**
 * Remove cookie
 *
 * @param name         Cookie name.
 */
function eraseCookie(name) {
  createCookie(name,"",-1);
}