css how to use part of css selector name in property code example

Example 1: css child selector

/*
	Descendant selectors are used to match to any nested element. 
	Child combinators, on the other hand, only match to the direct 
	child element and are defined by the greater than symbol. 
	The selector on the right must be the direct child of the element 
	on the left.
*/
/* child combinator */ 
  parent > child {...}

/* descendant selector */ 
  parent child {...}
  ancestor descendant {...}

Example 2: Which DOM method follows CSS syntax?

/*Do this for classes*/
document.querySelector(".example"); 
/*Do this for IDs*/
document.querySelector("#example");
/*This selects all of the elements in those groups*/