te')); return $arr; } /* 遍历用户所有主题 * @param $uid 用户ID * @param int $page 页数 * @param int $pagesize 每页记录条数 * @param bool $desc 排序方式 TRUE降序 FALSE升序 * @param string $key 返回的数组用那一列的值作为 key * @param array $col 查询哪些列 */ function thread_tid_find_by_uid($uid, $page = 1, $pagesize = 1000, $desc = TRUE, $key = 'tid', $col = array()) { if (empty($uid)) return array(); $orderby = TRUE == $desc ? -1 : 1; $arr = thread_tid__find($cond = array('uid' => $uid), array('tid' => $orderby), $page, $pagesize, $key, $col); return $arr; } // 遍历栏目下tid 支持数组 $fid = array(1,2,3) function thread_tid_find_by_fid($fid, $page = 1, $pagesize = 1000, $desc = TRUE) { if (empty($fid)) return array(); $orderby = TRUE == $desc ? -1 : 1; $arr = thread_tid__find($cond = array('fid' => $fid), array('tid' => $orderby), $page, $pagesize, 'tid', array('tid', 'verify_date')); return $arr; } function thread_tid_delete($tid) { if (empty($tid)) return FALSE; $r = thread_tid__delete(array('tid' => $tid)); return $r; } function thread_tid_count() { $n = thread_tid__count(); return $n; } // 统计用户主题数 大数量下严谨使用非主键统计 function thread_uid_count($uid) { $n = thread_tid__count(array('uid' => $uid)); return $n; } // 统计栏目主题数 大数量下严谨使用非主键统计 function thread_fid_count($fid) { $n = thread_tid__count(array('fid' => $fid)); return $n; } ?>javascript - Checking if form already exists - Stack Overflow

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    javascript - Checking if form already exists - Stack Overflow

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    Is there a better mand than this to check if a form is exists and if so submit it? Right now I'm using:

    if(document.forms[0])document.forms[0].submit()

    Which works, however if form[0] does not exist it throws an exception. I'm trying to keep this dynamic in the sense I don't know what the form ID or name is.

    Is there a better mand than this to check if a form is exists and if so submit it? Right now I'm using:

    if(document.forms[0])document.forms[0].submit()

    Which works, however if form[0] does not exist it throws an exception. I'm trying to keep this dynamic in the sense I don't know what the form ID or name is.

    • javascript
    Share Improve this question edited Nov 18, 2011 at 7:51 Claus Jørgensen 26.3k9 gold badges93 silver badges159 bronze badges asked Nov 18, 2011 at 6:44 JoeJoe 1,77210 gold badges43 silver badges60 bronze badges 2
    • If the problem is in JavaScript - I would not even tag this question as WP7 – Filip Skakun Commented Nov 18, 2011 at 7:19
    • 1 document.forms[0] is brittle, there can be more than 1 form on a page, and if the html changes your javascript is broken. that's why i propose using Ids on the form. – Jason Commented Nov 18, 2011 at 8:01
    Add a ment  | 

    4 Answers 4

    Reset to default 7

    To avoid the exception you could do:

    if (typeof document.forms[0] !== 'undefined') document.forms[0].submit();

    can you add an id to the form? can you use jquery?

    with id, no jquery

    var form = document.getElementById('my-form');
if (form != null) {
 form.submit();
}

    with id & jquery

    if ($("#my-form").length == 1) {
  $("#my-form").submit();
}

    If your only requirement is to check whether a form exists, and if so, submit the first form, you can use:

    if (document.forms.length) document.forms[0].submit();

    You can check for undefined :

    if(document.forms[0] != 'undefined')
    document.forms[0].submit()

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