Client Validation for SharePoint file Upload Control

we can set client side validation for SharePoint file upload / attachment control.
we can do validation on
 1. Restricted file types
2.  Max file Size
3. Min File Size

function CustomUpload() {

    var newFilePath = $('#attachmentsOnClient').find('input').last().val();   
    var newFileName = TrimWhiteSpaces(newFilePath).replace(/^.*[\\\/]/, '');
 var restrictype = ".ade|\\.adp|\\.asa|\\.ashx|\\.asmx|\\.asp|\\.bas|\\.bat|\\.cdx|\\.cer|\\.chm|\\.class|\\.cmd|\\.com|\\.config|\\.cnt|\\.cpl|\\.crt|\\.csh|\\.der|\\.dll|\\.exe|\\.fxp|\\.gadget|\\.grp|\\.hlp|\\.hpj|\\.hta|\\.htr|\\.htw|\\.ida|\\.idc|\\.idq|\\.ins|\\.isp|\\.its|\\.jse|\\.json|\\.ksh|\\.lnk|\\.mad|\\.maf|\\.mag|\\.mam|\\.maq|\\.mar|\\.mas|\\.mat|\\.mau|\\.mav|\\.maw|\\.mcf|\\.mda|\\.mdb|\\.mde|\\.mdt|\\.mdw|\\.mdz|\\.ms-one-stub|\\.msc|\\.msh|\\.msh1|\\.msh1xml|\\.msh2|\\.msh2xml|\\.mshxml|\\.msi|\\.msp|\\.mst|\\.ops|\\.pcd|\\.pif|\\.pl|\\.prf|\\.prg|\\.printer|\\.ps1|\\.ps1xml|\\.ps2|\\.ps2xml|\\.psc1|\\.psc2|\\.pst|\\.reg|\\.rem|\\.scf|\\.scr|\\.sct|\\.shb|\\.shs|\\.shtm|\\.shtml|\\.soap|\\.stm|\\.svc|\\.url|\\.vb|\\.vbe|\\.vbs|\\.vsix|\\.ws|\\.wsc|\\.wsf|\\.wsh|\\.xamlx";
    var maxFileNameLength = 128; 
 var maxFileSize = 250;
 //var extension = newFileName.replace(/^.*\./, '');
  var myFSO = new ActiveXObject("Scripting.FileSystemObject");
  var thefile = myFSO.getFile(newFilePath);
  var filesize = Math.round((thefile.size/1048576),2);
    
   
 
    var match = (new RegExp('[~#%\&{}+\|]|\\.\\.|^\\.|\\.$')).test(newFileName);
  var filetypes = (new RegExp(restrictype)).test(newFileName);
  
    if (match) {
        alert("Ivalid file name. The name of the attached file contains invalid characters.");
    }
    else if (newFileName.length > maxFileNameLength) {
        alert("Ivalid file name. The name of the attached file is too long.");
    }
  else if (newFileName.length <= 0) {
        alert("Please select a file");
    }
 else if(filetypes) {
  alert("Ivalid file type. The attached file type is restricted by SharePoint.");
   return false;
 } 
 else if(filesize > maxFileSize) {
  alert("The attached file size exceeds size limit of 250MB.");
   return false;
   
 } 

} 

Now we will include all feature step by Step

Step: 1
   
SharePoint Custom file attachment control

Step: 2
 Stop Showing duplicate file upload Error

Step: 3
 SharePoint add comments for each attached document