javascript - alert() doesn't show the value in a Tampermonkey script -

i'm trying make tampermonkey script unhide 1 div defined that

<div id="div2" style="display: none;">  

my script doesn't work , don't know why...

// ==userscript==  // @name            actualisation vérification infra  // @namespace       http://use.i.e.your.homepage/  // @version         0.1  // @description     permet de recharger la page toutes les x millisecondes afin de garder la session active  // @match           https://reportingogd.truc.fr/reporting/affichersynthese.do*  // @copyright       2013+, pcu team  // ==/userscript==   var extern = document.getelementbyid('div2').style.display;  alert('extern');   // refresh toutes les xx minutes   var delay = "30m"; // remplacer par le temps souhaité, 1s, 10s, 60s, 1m, 15m, 30m, 1h, 3h, ...   var t = parseint(delay.match(/\d+/)[0], 10),          unit = "",          d = 0;  switch(delay.match(/[ms]/i)[0]) {          case "s":                  unit = "secondes";                  d = t * 1000;                  break;          case "m":                  unit = "minutes";                  d = t * 60000;                  break;          case "h":                  unit = "heures";                  d = t * 3600000;                  break;  }   setinterval("window.location.reload()", d);   alert("vous n'aviez pas activé la page depuis " + t + " " + unit); 

when want show var "extern", pop-up give "extern" , not value of div...

please me ?

ps : second part of code work properly, it's refresh of web page

your alert alerts 'extern' because alert string.

alert(extern) alert value.

and make div visible, just:

document.getelementbyid('div2').style.display = 'block';