File Upload not leaving file path

function fileCheck(obj)
        {
            var fileUploadPath = obj.value;
            var fileSize = obj.files[0].size;
            var extension = fileUploadPath.substring(fileUploadPath.lastIndexOf('.') + 1).toLowerCase();
            if (extension == "gif" || extension == "png" || extension == "bmp" || extension == "jpeg" || extension == "jpg")
            {

            }
            else
            {
                alert("Photo only allows file types of GIF, PNG, JPG, JPEG and BMP.");
       Clear();return false;
            }
            if (fileSize > 1024)
            {
                alert("Photo size should not exceeds 1 MB");
          Clear();
                return false;
            }

function Clear()
 {
 var clrFile = document.getElementById("FileUpload1");
 clrFile.select();
 var clr=clrFile.createTextRange();
 clr.execCommand('delete');
 clrFile.focus();

 }