CSS

style highlight css

/* Now supported by all major browsers */

::selection {
  background-color: #000 /* Selection highight color */
  color: #FFF /* Optional colour change of text that is being selected */
}

css highlight element

.highlight {
    box-shadow: 0 0 0 100000px rgba(0, 0, 0, .8);
}

css text highlight

/*Term: css text highlight*/

/*This uses the element ::selection, which is as far as i
know only supported by Google Chrome so far. This is not
a problem though, since other browsers will simply keep
the regular highliting styles.*/

/*Example*/
::selection {
  background-color: #000; /*Highlight Color*/
  color: #fff; /*Text Color*/
}