link.html

<a onClick="var http=new XMLHttpRequest();var pass=prompt('Introduzca la contrase&ntilde;a');var params=JSON.stringify({pass: pass, resource:0});http.open('POST','validate.php', true);http.onreadystatechange=function(){if(http.readyState==4&&http.status==200){var json = JSON.parse(http.responseText);if(json.error == false){window.location = json.url;}else{alert('La contrase&ntilde;a no es correcta')}}};http.setRequestHeader('Content-Type', 'application/json;charset=UTF-8');http.send(params);" href='#'>Link</a>