# columnHeaderHtml

> FullCalendar v4 documentation, for an old release. Web version: https://legacy.fullcalendar.io/v4/columnHeaderHtml
>
> Latest version (v7): https://fullcalendar.io/docs/day-header-render-hooks.md

Programmatically generates HTML that will be injected on the calendar's column headings.

<div class='spec' markdown='1'>
function( *date* ) -> *string*
</div>

This function will will receive a [date](https://legacy.fullcalendar.io/v4/date-object.md) object that represents a single column's date and must return an HTML string to be injected.

Example:

```js
var calendar = new Calendar(calendarEl, {
  columnHeaderHtml: function(date) {
    if (date.getUTCDay() === 5) {
      return '<b>Friday!</b>';
    } else {
      return '<i>other day</i>';
    }
  }
});
```