how to check input type file is empty or not in jquery before submit code example

Example 1: javascript check if object is empty

function isObjectEmpty(obj) {
    return Object.keys(obj).length === 0;
}

Example 2: check if string is number or not php

$var_num = "1";
$var_str = "Hello World";

var_dump( is_numeric($var_num), is_numeric($var_str) );

/* 
Output -
 bool(true)
 bool(false)
*/