Available border styles

Style name PHPExcel class reference
none PHPExcel_Style_Border::BORDER_NONE
dashDot PHPExcel_Style_Border::BORDER_DASHDOT
dashDotDot PHPExcel_Style_Border::BORDER_DASHDOTDOT
dashed PHPExcel_Style_Border::BORDER_DASHED
dotted PHPExcel_Style_Border::BORDER_DOTTED
double PHPExcel_Style_Border::BORDER_DOUBLE
hair PHPExcel_Style_Border::BORDER_HAIR
medium PHPExcel_Style_Border::BORDER_MEDIUM
mediumDashDot PHPExcel_Style_Border::BORDER_MEDIUMDASHDOT
mediumDashDotDot PHPExcel_Style_Border::BORDER_MEDIUMDASHDOTDOT
mediumDashed PHPExcel_Style_Border::BORDER_MEDIUMDASHED
slantDashDot PHPExcel_Style_Border::BORDER_SLANTDASHDOT
thick PHPExcel_Style_Border::BORDER_THICK
thin PHPExcel_Style_Border::BORDER_THIN