如何使用jquery检查输入类型=“文件”是否有文件？

Question

我的页面中有一个文件上传控件<input id="File1" type="file" /> ...如何检查输入类型=“文件”是否有文件或者在点击按钮upload使用jquery？

Answer 1

if (jQuery('#File1').val()) { /* There are files */ }

Answer 2

You should use "required" instead of JQuery. By just one attribute it'll check input=file has file or not. Example:

<input type="file" required/>

Answer 3

$('#upload').bind('click', function(e){
   if( $('#File1').val() != ""){
       // file selected
   }
   else{
       // no file selected
   }
});