如果单击php后如何禁用提交按钮?

I have a send button at the end of the form but I do not know how to disable it in the onClick.

echo "<input type='submit' name='add' value=\"".$LANG['help'][14]."\" class='submit' >";

you can use

echo "<input type='submit' name='add' onclick="this.form.submit(); this.disabled = true;"  value=\"".$LANG['help'][14]."\" class='submit' >";

You can try following code

echo "<input type='submit' name='add' onclick="this.disabled = true; this.form.submit();"  value=\"".$LANG['help'][14]."\" class='submit' >";

please try this

$('input[type="submit"]').click(function() {
    this.disabled = true;
};