set placeholder javascript

::-webkit-input-placeholder {color: pink;} /* Chrome/Opera/Safari */
::-moz-placeholder { color: pink;} /* Firefox 19+ */
:-ms-input-placeholder { color: pink;} /* IE 10+ */
:-moz-placeholder {color: pink;}  /* Firefox 18- */

<form action="/action_page.php">
	<label for="phone">Enter a phone number:</label>
    <input type="tel" id="phone" name="phone" placeholder="123-45-678" pattern="[0-9]{3}-[0-9]{2}-[0-9]{3}"><br><br>
 </form> 
 

document.querySelector('.gfield_list_cell.gfield_list_72_cell3 input').setAttribute('placeholder','$');