js 判断 input 输入框不能为空的方法 | 2019-01

<div class="form-group">
    <label class="col-sm-2 control-label">标题：</label>
    <div class="col-sm-4">
        <input type="text"  id = "title" class="form-control" placeholder="请输入广告标题（必填，10个字以内）" maxlength="10" name="title" value="${adMaterial.text1}"></div>
    <div  class="col-sm-6 form-control-static"></div>
</div>
 
<input type="submit" value="提交" class="btn btn-orange" onclick="return checkStr()"></div>
<button type="submit" class="btn btn-primary" onclick="return check()">

<script type="text/javascript">
    function check()
    {
        if($('#deny_message').val()=="")
        {
            alert("请输入拒绝原因");
            return false;
        } else {
            return true;
        }
    }
</script>

onclick="return check()"和onclick="check()"区别