//var exts = "jpg|gif|png|bmp|mp3|mpg|mpeg|avi|rar|zip|7z|gz|txt|avi|mpg";
// var exts = ".*"; //Use this to accept all Extensions
var exts = "txt|doc|xls|xlsx|pdf"; //Text Files, Word Files, Excel Files Only

function StartUpload(f1)
{
    if(f1.file_1.value==""){alert('Select at least one file to upload');return false;};
    if(!checkExt(f1.file_1.value))return false;
    var UID = Math.round(10000*Math.random())+'0'+Math.round(10000*Math.random());
    f1.action = f1.action.split('?')[0]+'?upload_id='+UID;
    if(f1.popup.checked)
    {
      win1 = window.open(f1.action.split('upload.cgi')[0]+'upload_status.cgi?upload_id='+UID,'win1','width=320,height=240,resizable=1');
      win1.window.focus();
    }
    return true;
}

function checkExt(value)
{
    if(value=="")return true;
    var re = new RegExp("^.+\.("+exts+")$","i");
    if(!re.test(value))
    {
        alert("This file extension is not allowed: \n" + value + "\n\nOnly these extensions are allowed: "+exts.replace(/\|/g,',')+" \n\n");
        return false;
    }
    return true;
}