使用Javascript进行文件类型验证 [英] File type validation with Javascript

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本文介绍了使用Javascript进行文件类型验证的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我对JavaScript验证有疑问。每当我的脚本运行时,我都会验证< input type =file> ,它会验证,但也会调用操作页面。我想停止操作页面,直到验证完成。这是我的代码,任何帮助都会很棒。问候

I have a question regarding to JavaScript validation. I am validaing the <input type="file"> whenever my scripts runs, it validates but also the action page is called. I want to stop the action page until the validation is complete. Here is my code, any help will be awesome. Regards

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Image Uploading</title>
    </head>


    <body>
        <form name="xx" action="server.php" method="post" enctype="multipart/form-data" onsubmit="Checkfiles(this)">
            <input type="file" name="file_uploading" id="filename">
            <input type="submit" value="Submit" name="uploadfile">
        </form>

        <form name="view" method="post">
            <a href="view_server.php">View your uploaded Images</a>
        </form>
    </body>
</html>

<script type="text/javascript">
    function Checkfiles()
    {
        var fup = document.getElementById('filename');
        var fileName = fup.value;
        var ext = fileName.substring(fileName.lastIndexOf('.') + 1);

    if(ext =="GIF" || ext=="gif")
    {
        return true;
    }
    else
    {
        alert("Upload Gif Images only");
        return false;
    }
    }
</script>


推荐答案

var fname = "the file name here.ext"; 
var re = /(\.jpg|\.jpeg|\.bmp|\.gif|\.png)$/i;
if(!re.exec(fname))
{
alert("File extension not supported!");
}

这篇关于使用Javascript进行文件类型验证的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!

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