|  | <!DOCTYPE html> | 
|  | <html> | 
|  | <head> | 
|  | <meta charset="utf-8"> | 
|  | <title>CSS Backgrounds and Borders Module Level 4: parsing background-position-x with invalid values</title> | 
|  | <link rel="help" href="https://drafts.csswg.org/css-backgrounds-4/#propdef-background-position-x"> | 
|  | <meta name="assert" content="background-position-x supports only the grammar '[ center | [ left | right | x-start | x-end ]? <length-percentage>? ]#'."> | 
|  | <script src="/resources/testharness.js"></script> | 
|  | <script src="/resources/testharnessreport.js"></script> | 
|  | <script src="/css/support/parsing-testcommon.js"></script> | 
|  | </head> | 
|  | <body> | 
|  | <script> | 
|  | test_invalid_value("background-position-x", "top"); | 
|  | test_invalid_value("background-position-x", "bottom"); | 
|  | test_invalid_value("background-position-x", "y-start"); | 
|  | test_invalid_value("background-position-x", "y-end"); | 
|  | test_invalid_value("background-position-x", "center 10px"); | 
|  | test_invalid_value("background-position-x", "20% left"); | 
|  | test_invalid_value("background-position-x", "right left"); | 
|  | test_invalid_value("background-position-x", "x-start center"); | 
|  | test_invalid_value("background-position-x", "left, center right"); | 
|  | </script> | 
|  | </body> | 
|  | </html> |