<script>
// возвращает cookie если есть или undefined
function getCookie(name) {
     var matches = document.cookie.match(new RegExp(
       "(?:^|; )" + name.replace(/([\.$?*|{}\(\)\[\]\\\/\+^])/g, '\\$1') + "=([^;]*)"
     ))
     return matches ? decodeURIComponent(matches[1]) : undefined  
}
   
// уcтанавливает cookie
function setCookie(name, value, props) {
     props = props || {}
     var exp = props.expires
     if (typeof exp == "number" && exp) {
         var d = new Date()
         d.setTime(d.getTime() + exp*1000)
         exp = props.expires = d
     }
     if(exp && exp.toUTCString) { props.expires = exp.toUTCString() }
   
     value = encodeURIComponent(value)
     var updatedCookie = name + "=" + value
     for(var propName in props){
         updatedCookie += "; " + propName
         var propValue = props[propName]
         if(propValue !== true){ updatedCookie += "=" + propValue }
     }
     document.cookie = updatedCookie
   
}
   
// удаляет cookie
function deleteCookie(name) {
     setCookie(name, null, { expires: -1 })
}
</script>

<script language="JavaScript">
if (!getCookie('pswd')) {
if (top.location.search=="") {
pass = prompt('Введите ЛИЧНЫЙ КОД','');
setCookie('pswd', 'xxx', {expires: 86400})
if (pass=='место пароля')
{  } else { top.location.href="error.htm" }
}
}
</script>