Javascript 如果给定的文件格式错误,请重置输入文件

Javascript 如果给定的文件格式错误,请重置输入文件,javascript,Javascript,如果文件格式不是图像格式,如何将输入文件设置回“未选择文件” <input type="file" name="image" id="image" value="" class="form-control" /> <script> $("#image").change(function() { var Data = document.getElementById('image'); var FileUploadPath = Data.value;

如果文件格式不是图像格式,如何将输入文件设置回“未选择文件”

<input type="file" name="image" id="image" value="" class="form-control" />

<script>
$("#image").change(function()
{
    var Data = document.getElementById('image');
    var FileUploadPath = Data.value;

    if (FileUploadPath != '') {
        var Extension = FileUploadPath.substring(FileUploadPath.lastIndexOf('.') + 1).toLowerCase();
        //The file uploaded is an image

        if (Extension == "gif" || Extension == "png" || Extension == "bmp"
                            || Extension == "jpeg" || Extension == "jpg"){
            return true;
        }else if (Extension != 'gif' || Extension != 'png' || Extension != 'bmp' || Extension != 'jpeg' || Extension != 'jpg') {

            alert("Photo only allows file types of GIF, PNG, JPG, JPEG and BMP. ");
            return false;
        }
    }
}); 
</script>

$(“#图像”).change(函数()
{
var Data=document.getElementById('image');
var FileUploadPath=Data.value;
如果(文件上传路径!=''){
var Extension=FileUploadPath.substring(FileUploadPath.lastIndexOf('.')+1.toLowerCase();
//上传的文件是一个图像
如果(扩展名==“gif”| |扩展名==“png”| |扩展名==“bmp”
||分机==“jpeg”| |分机==“jpg”){
返回true;
}else if(扩展名!=“gif”|扩展名!=“png”|扩展名!=“bmp”|扩展名!=“jpeg”|扩展名!=“jpg”){
警告(“照片只允许文件类型为GIF、PNG、JPG、JPEG和BMP。”);
返回false;
}
}
}); 
$(“#图像”).change(函数()
{
var Data=document.getElementById('image');
var FileUploadPath=Data.value;
如果(文件上传路径!=''){
var Extension=FileUploadPath.substring(FileUploadPath.lastIndexOf('.')+1.toLowerCase();
//上传的文件是一个图像
如果(扩展名==“gif”| |扩展名==“png”| |扩展名==“bmp”
||分机==“jpeg”| |分机==“jpg”){
返回true;
}else if(扩展名!=“gif”|扩展名!=“png”|扩展名!=“bmp”|扩展名!=“jpeg”|扩展名!=“jpg”){
警告(“照片只允许文件类型为GIF、PNG、JPG、JPEG和BMP。”);
Data.type='';
Data.type='file';
返回false;
}
}
});

您可以将值设置为空字符串

$(“#图像”).change(函数()
{
var Data=document.getElementById('image');
var FileUploadPath=Data.value;
如果(文件上传路径!=''){
var Extension=FileUploadPath.substring(FileUploadPath.lastIndexOf('.')+1.toLowerCase();
//上传的文件是一个图像
如果(扩展名==“gif”| |扩展名==“png”| |扩展名==“bmp”| |扩展名==“jpeg”| |扩展名==“jpg”){
返回true;
}else if(扩展名!=“gif”|扩展名!=“png”|扩展名!=“bmp”|扩展名!=“jpeg”|扩展名!=“jpg”){
警告(“照片只允许文件类型为GIF、PNG、JPG、JPEG和BMP。”);
Data.value=“”;
返回false;
}
}
});

文件上传