权限没有,则隐藏 function forum_list_access_filter($forumlist, $gid, $allow = 'allowread') { global $grouplist; if (empty($forumlist)) return array(); if (1 == $gid) return $forumlist; $forumlist_filter = $forumlist; $group = $grouplist[$gid]; foreach ($forumlist_filter as $fid => $forum) { if (empty($forum['accesson']) && empty($group[$allow]) || !empty($forum['accesson']) && empty($forum['accesslist'][$gid][$allow])) { unset($forumlist_filter[$fid]); } unset($forumlist_filter[$fid]['accesslist']); } return $forumlist_filter; } function forum_filter_moduid($moduids) { $moduids = trim($moduids); if (empty($moduids)) return ''; $arr = explode(',', $moduids); $r = array(); foreach ($arr as $_uid) { $_uid = intval($_uid); $_user = user_read($_uid); if (empty($_user)) continue; if ($_user['gid'] > 4) continue; $r[] = $_uid; } return implode(',', $r); } function forum_safe_info($forum) { //unset($forum['moduids']); return $forum; } function forum_filter($forumlist) { foreach ($forumlist as &$val) { unset($val['brief'], $val['announcement'], $val['seo_title'], $val['seo_keywords'], $val['create_date_fmt'], $val['icon_url'], $val['modlist']); } return $forumlist; } function forum_format_url($forum) { global $conf; if (0 == $forum['category']) { // 列表URL $url = url('list-' . $forum['fid'], '', FALSE); } elseif (1 == $forum['category']) { // 频道 $url = url('category-' . $forum['fid'], '', FALSE); } elseif (2 == $forum['category']) { // 单页 $url = url('read-' . trim($forum['brief']), '', FALSE); } if ($conf['url_rewrite_on'] > 1 && $forum['well_alias']) { if (0 == $forum['category'] || 1 == $forum['category']) { $url = url($forum['well_alias'], '', FALSE); } elseif (2 == $forum['category']) { // 单页 $url = ($forum['threads'] && $forum['brief']) ? url($forum['well_alias'] . '-' . trim($forum['brief']), '', FALSE) : url($forum['well_alias'], '', FALSE); } } return $url; } function well_forum_alias() { $forumlist = forum_list_cache(); if (empty($forumlist)) return ''; $key = 'forum-alias'; static $cache = array(); if (isset($cache[$key])) return $cache[$key]; $cache[$key] = array(); foreach ($forumlist as $val) { if ($val['well_alias']) $cache[$key][$val['fid']] = $val['well_alias']; } return array_flip($cache[$key]); } function well_forum_alias_cache() { global $conf; $key = 'forum-alias-cache'; static $cache = array(); // 用静态变量只能在当前 request 生命周期缓存,跨进程需要再加一层缓存:redis/memcached/xcache/apc if (isset($cache[$key])) return $cache[$key]; if ('mysql' == $conf['cache']['type']) { $arr = well_forum_alias(); } else { $arr = cache_get($key); if (NULL === $arr) { $arr = well_forum_alias(); !empty($arr) AND cache_set($key, $arr); } } $cache[$key] = empty($arr) ? '' : $arr; return $cache[$key]; } ?>html - Traffic light Sequence Javascript - Stack Overflow
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html - Traffic light Sequence Javascript - Stack Overflow

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Here is my code for a traffic light's sequences. I was wondering how I could add a timer in to change the traffic light colour every 3 seconds, for example, when the button is clicked. Thanks!

<!DOCTYPE html> 
<html> 
<body>  
  <h1>JavaScript Task 3</h1> 
  <p>This is  my Traffic Light script</p> 
  <img id="light" src="./assets/red.jpg">
  <button type="button" onclick="changeLights()">Change Lights</button>  
  <script> 
    var list = ["./assets/red.jpg","./assets/redamber.jpg", "./assets/green.jpg","./assets/amber.jpg" ];
    var index = 0;
    function changeLights() {
      index = index + 1;      
      if (index == list.length) 
        index = 0;      
      var image = document.getElementById('light');     
      image.src = list[index]; 
    } 
  </script>  
</body> 
</html>   

Here is my code for a traffic light's sequences. I was wondering how I could add a timer in to change the traffic light colour every 3 seconds, for example, when the button is clicked. Thanks!

<!DOCTYPE html> 
<html> 
<body>  
  <h1>JavaScript Task 3</h1> 
  <p>This is  my Traffic Light script</p> 
  <img id="light" src="./assets/red.jpg">
  <button type="button" onclick="changeLights()">Change Lights</button>  
  <script> 
    var list = ["./assets/red.jpg","./assets/redamber.jpg", "./assets/green.jpg","./assets/amber.jpg" ];
    var index = 0;
    function changeLights() {
      index = index + 1;      
      if (index == list.length) 
        index = 0;      
      var image = document.getElementById('light');     
      image.src = list[index]; 
    } 
  </script>  
</body> 
</html>   
Share Improve this question edited May 15, 2016 at 0:21 Jonathan Eustace 2,48713 gold badges34 silver badges54 bronze badges asked Apr 28, 2016 at 16:22 K. SmithK. Smith 331 gold badge1 silver badge9 bronze badges 5
  • 2 setInterval(changeLights,3000)... – Niet the Dark Absol Commented Apr 28, 2016 at 16:23
  • Has your teacher taught you about setTimeout or setInterval? – Mike Cluck Commented Apr 28, 2016 at 16:23
  • 1 stackoverflow./questions/36920320/… stackoverflow./questions/34653900/… stackoverflow./questions/37906626/… stackoverflow./questions/35920989/… stackoverflow./questions/31747318/… stackoverflow./questions/37796563/… – le_m Commented Jun 21, 2016 at 9:21
  • Can we auto tag "traffic light sequence" questions as duplicates? – evolutionxbox Commented Feb 17, 2017 at 9:58
  • Sure, feel free – K. Smith Commented Feb 21, 2017 at 19:13
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2 Answers 2

Reset to default 2

Use the setInterval function.

The first parameter is the function you want to call and the second parameter is how often it should be called, in milliseconds.

var timer = setInterval(changeLights,3000);

var list = ["./assets/red.jpg","./assets/redamber.jpg",     "./assets/green.jpg","./assets/amber.jpg" ];
var index = 0;
function changeLights() {
     index = index + 1;      
if (index == list.length) 
index = 0;      
var image = document.getElementById('light');     
image.src=list[index]; } 
  var timer = setInterval(changeLights,3000);
<h1>JavaScript Task 3</h1> 
<p>This is  my Traffic Light script</p> 
<img id="light" src="./assets/red.jpg"> <button type="button" 
onclick="changeLights()">Change Lights</button>  

You can set a static timer with setTimeout(function, time);

In your case, if you want a repeating timer every 3 seconds constantly, you can have setTimeout run every time the changeLights() function ends

See w3schools article on timing

var timer;
function changeLights() {
    index = index + 1;      
    if (index == list.length) 
    index = 0;      
    var image = document.getElementById('light');     
    image.src=list[index];

    timer = setTimeout("changeLights", 3000);
}

With that change, once you start the lights, the function will repeat every 3 seconds.

The timer variable also alows you to stop the timer (perhaps in your case with another button) with:

clearTimeout(timer);

Hope this helps

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