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]; } ?>javascript - Find the first character of input in a textbox - Stack Overflow
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javascript - Find the first character of input in a textbox - Stack Overflow

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I am stuck in implementing the following:

  1. User starts typing in a textbox.
  2. The javascript on page captures the first character typed, validates that it is an english alphabet (a-z,A-Z) and converts it to lowercase (if necessary).
  3. Make an XMLHttp request based on the input (i.e. if first input character is a, get a.xml, if b get b.xml and so on).

I know how to do the last part (make the xmlhttp request) but am kind of stuck on how to capture the first character and validate it (in a way that works on all browsers). Please guide. Thanks.

Clarification: This is to create a Google Suggest like autoplete-drop-down menu without the need for server side programs.

I am stuck in implementing the following:

  1. User starts typing in a textbox.
  2. The javascript on page captures the first character typed, validates that it is an english alphabet (a-z,A-Z) and converts it to lowercase (if necessary).
  3. Make an XMLHttp request based on the input (i.e. if first input character is a, get a.xml, if b get b.xml and so on).

I know how to do the last part (make the xmlhttp request) but am kind of stuck on how to capture the first character and validate it (in a way that works on all browsers). Please guide. Thanks.

Clarification: This is to create a Google Suggest like autoplete-drop-down menu without the need for server side programs.

Share Improve this question edited Jul 4, 2010 at 9:03 Justin Johnson 31.3k7 gold badges66 silver badges89 bronze badges asked Feb 15, 2010 at 18:59 SamSam 1,3885 gold badges16 silver badges30 bronze badges 1
  • What's the application? This example seems a little abstract and contrived. – Dustman Commented Feb 15, 2010 at 19:04
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2 Answers 2

Reset to default 3

Something like this should work:

HTML:

<input type="text" id="myField" />

And in JS:

window.onload = function() {
    document.getElementById('myField').onkeyup = function() {
        // Validate that the first letter is A-Za-z and capture it
        var letter = this.value.match(/^([A-Za-z])/);

        // If a letter was found
        if(letter !== null) {
            // Change it to lowercase and update the value
            letter = letter[0].toLowerCase();
            this.value = letter + this.value.substring(1);

            // Do the request
        }
    }
}

My vanilla-JS skills are a bit rusty but this should do the trick. Just for the heck of it, here's the same using jQuery:

$(function() {
    $('#myField').keyup(function() {
        var letter = $(this).val().match(/^([A-Za-z])/);

        // If a letter was found
        if(letter !== null) {
            // Change it to lowercase and update the value
            letter = letter[0].toLowerCase();
            $(this).val(letter + $(this).val().substring(1);

            // Do the request
        }
    });
});

What part of the problem do you not know how to do? Here's an approach that you can follow. Very likely to need adjustments, but a good starting point

if our text field's id is 'txt'

document.getElementByID('txt').onkeypress = function(e) {
  var textInField = this.value;
  if (textInField.length == 1) {
    var firstChar = textInField.charAt(0);
    if (/[a-zA-Z]/.test(firstChar)) {
      sendXHR(textInField.value.toLowerCase())
    }
  } else {
    // What do you do if there is one or more chars???
  }
}

Note that the other answers here mention onchange, that doesn't fire until the focus leaves the field, which I don't think is what you want

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