How to check an input type="file" has a file or not using jquery?

I have a file upload control <input id="File1" type="file" /> in my page... How to check an input type="file" has a file or not using jquery on click of 开发者_开发技巧a button upload?

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

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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/>

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