获取输入类型文件的值,如果为空则发出警报

Question

如果输入类型文件为空,如何提醒!

这是我的jquery代码,但我不知道如何获得该值

$('.upload').live("click",function()
{
    var imgVal = $('#uploadImage').val();
    if(imgVal=='')
    {
        alert("empty input file");

    }
    return false;

});


<input type="file" name="image" id="uploadImage" size="30" />
<input type="submit" name="upload"  class="send_upload" value="upload" />

Answer 1

<script type="text/javascript">
$(document).ready(function() {
    $('#upload').bind("click",function() 
    { 
        var imgVal = $('#uploadImage').val(); 
        if(imgVal=='') 
        { 
            alert("empty input file"); 

        } 
        return false; 

    }); 
});
</script> 

<input type="file" name="image" id="uploadImage" size="30" /> 
<input type="submit" name="upload" id="upload"  class="send_upload" value="upload" /> 

Answer 2

应该有

$('.send_upload')

但不是 $('.upload')