javascript - 不工作更正我的 javascript 代码以验证文件大小？

Question

我用 php 和 javascript 设计了一个用于上传成员(member)照片的表单。

我有一个用于在服务器端验证上传表单的 PHP 代码，还有一个用于在客户端验证上传表单的代码。PHP 代码工作正常，但 javascript 代码在检查文件大小和错误表示时显示警告。如果文件大于 100 KB，它会提醒但不会停止上传文件。

javascript 验证码是:

   <script language="javascript">
       function findSize()
       {
            var fileInput =  document.getElementById("fileup");
            try{
                var fsize=fileInput.files[0].size;
                var fsizekb1=fsize/1024;
                if(fsizekb1>100)
                {
                    //alert(fileInput.files[0].size+"vv"); // Size returned in bytes.
                    alert("your file is bigger than 100 KB and size of your file is "+fsizekb1.toFixed(2)+" KB");
                    return false;
                }
            }catch(e){

                var objFSO = new ActiveXObject("Scripting.FileSystemObject");
                var e = objFSO.getFile( fileInput.value);
                var fileSize = e.size;

                var fsizekb=filesize/1024;
                if(fsizekb>100)
                {
                    //alert(fileSize);
                    alert("your file is bigger than 100 KB and size of your file is "+fsizekb1.toFixed(2)+" KB");
                    return false;
                }
            }
            return true;
        }

    function up_control()
      {

            if(document.forms["frm_up"]["up"].value=='')
            {
            alert ("please select your photo by Browse");
            return false;  
            }
        if(document.forms["frm_up"]["cptch"].value=='')
            {
            alert ("please write the picture code");
            return false;
            }

            findsize();

      return true;
      }
    </script>

上传表单是这样的:

<form method="post" enctype="multipart/form-data" name="frm_up" onSubmit="return up_control()">
<input id="fileup" style=" margin-right:3%;" type="file" name="up" accept="image/jpeg,image/x-png,.jpg"  ><br> <br>


<!--===========start Area==Captcha====================================================================================
=====================================================================================================================
=====================================================================================================================
-->


    <img style="" HEIGHT="55px" src="cptch.php?cpf=<?php echo rand(1111,999999999); ?>" id='captchaimg' border="2" >&nbsp;&nbsp;&nbsp;&nbsp;<br>
    <label  for="message" style="margin-right:1%">write number in above picture:</label><br>
    <input style="width: 8em" id="cptch" name="cptch" type="text" autocomplete="off" ><br>
    <Label  style="margin-right:1%;" id="captex_chng_lbl">Can't Read the picture?  <br id="br_cap_chng"><a href='javascript: refreshCaptcha();' style="color:#909;" id="rmz2" class="captex_chng">Change</a></label><br><br>
    <script language='JavaScript' type='text/javascript'>
        function refreshCaptcha()
        {
            var img = document.images['captchaimg'];
            img.src = img.src.substring(0,img.src.lastIndexOf("?"))+"?cpf="+Math.random()*1000;
        }

    </script>

<!--===========END Area==Capcha======================================================================================
=====================================================================================================================
=====================================================================================================================
-->
<input type="hidden" name="upl" value="1">

<input style=" margin-right:3% !important;" type="submit" value="  Send to see " >&nbsp;<input type="button" style="background-color:#FF8080; margin-right:5%;"  value="&nbsp;&nbsp;&nbsp;cancel  &nbsp;&nbsp;&nbsp;" onClick="document.location='index.php?c=regm'" ><br><br>
</form> 

为什么javascript代码在验证图片大小功能时不能正常工作，并且在显示错误(警告)后不阻止文件上传？

Answer 1

首先，我感谢 MagnusEriksson 提供的良好指导。但是最后一行是为了一切正确，必须返回真值的时候，但是通过在中的findsize()函数前加上return up_control() 问题已解决。