var parentId = parentId;
   console.log('pId'+parentId);

var filesToUpload = input.files;

for(var i = 0, f; f = filesToUpload[i]; i++)
{
    var reader = new FileReader();

    // Keep a reference to the File in the FileReader so it can be accessed in callbacks
    reader.file = f;

    reader.onerror = function(e)
    {
        switch(e.target.error.code)
        {
            case e.target.error.NOT_FOUND_ERR:
                alert('File Not Found!');
                break;
            case e.target.error.NOT_READABLE_ERR:
                alert('File is not readable');
                break;
            case e.target.error.ABORT_ERR:
                break; // noop
            default:
                alert('An error occurred reading this file.');
        };
    };

    reader.onabort = function(e)
    {
        alert('File read cancelled');
    };

    reader.onload = function(e)
    {
        var att = new sforce.SObject("Attachment");
        //sforce.connection.serverUrl = '{!$Site.Prefix}/services/Soap/u/40.0';
        att.Name = this.file.name;
        att.ContentType = this.file.type;
        att.ParentId = parentId;
        alert("hello1" + parentId);

       var binary = "";

att.Body = (new sforce.Base64Binary(binary)).toString();
        console.log('yt'+att.Body);
         alert(att);

         sforce.connection.create([att],
        {
            onSuccess : function(result, source)
            {
                if (result[0].getBoolean("success"))
                {
                    console.log("new attachment created with id " + result[0].id);
                    alert(result[0].id + "success");
                }
                else
                {
                    console.log("failed to create attachment " + result[0]);
                    alert("fail");
                    sforce.debug.open();

                }
            },
            onFailure : function(error, source)
            {
                alert("ERROR"+error);
                console.log("An error has occurred " + error+ result[0]);

            }
        });
    };

    var hello=reader.readAsArrayBuffer(f);
       }

actionfunctionname();


}