html - JavaScript - RegEx for time or a specific string -

in form have field asks user time me call them.

the code input follows (excluding <form> tags):

<p>    <label>when can call you?:</label>    <br>    <input type="text" name="contactconvenience" placeholder="hh:mm or &#34;anytime&#34;" onchange="checkcalltime()"> </p> <div id="callbackwarn"></div> 

i want use regex check whether user has entered time in format hh:mm or specific string "anytime", code i'm using doesn't work.

var callback = /^\d{2}([:]\d{2})$/;  var callbackanytime = str.match(/anytime/g);  function checkcalltime() {     var valid = true;      if ((!callback.test(document.bookingsform.contactconvenience.value)) || (!callbackanytime.test(document.bookingsform.contactconvenience.value))) {         document.bookingsform.contactconvenience.style.border = "1px solid red";         document.getelementbyid("callbackwarn").innerhtml = "enter time in format hh:mm or type \"anytime\".";         document.bookingsform.contactconvenience.title = "please enter time in format hh:mm or type \"anytime\".";         document.getelementbyid("callbackwarn").style.display = "block";         valid = false;     } else {         document.bookingsform.contactconvenience.style.border = "1px inset #ebe9ed";         document.bookingsform.contactconvenience.style.borderradius = "2px";         document.getelementbyid("callbackwarn").style.display = "none";     } } 

as can see have use 2 separate regex expressions, 1 matching time in format hh:mm; , other matching specific string "anytime".

in function itself, i'm using || see if either of regexs have been matched or not.

nb: aware i'm using onchange rather onsubmit, <form> tag consists of onsubmit calling on master function.

assumming 00:00 midnight;

var callback = /^(([01]\d|2[0-3]):([0-5]\d)|anytime)$/;  if (!callback.test(document.bookingsform.contactconvenience.value)) {    // error code }