报错解决：Uncaught ReferenceError: Invalid left-hand side in assignment

Error resolution:
Screenshot of Uncaught ReferenceError: Invalid left-hand side in assignment error report:

Translated as: the left side of the assignment is invalid

Reason: modify the attribute of background-color in javaScript

Error code: This code is written inside the javaScript, I use CSS styles to the background-color, but the script language does not support the use of "-" to name, so the error, the correct wording should be used directly hump nomenclature , To use the background-color property.
hid.style.background-color = "#ddd";
hid.style.backgroundColor = "#ddd";