How to check if current time falls within a specific range on a week day using jquery/javascript?

This should hopefully help:

function checkTime() {
    var d = new Date(); // current time
    var hours = d.getHours();
    var mins = d.getMinutes();
    var day = d.getDay();

    return day >= 1
        && day <= 5
        && hours >= 9 
        && (hours < 17 || hours === 17 && mins <= 30);
}

Using the current time you could do something like this:

var now = new Date(),
    day = now.getDay(),
    hours = now.getHours();

//Check if day is Mon-Fri
if(0 < day < 6) {
  //check between 9am and 5pm
  if(9 <= hours <= 17) {
     if(hours !== 17 || now.getMinutes() <= 30) {
          //your jQuery code here
     }
  }
}

var now = new Date();
var dayOfWeek = now.getDay();
if(dayOfWeek > 0 && dayOfWeek < 6){
   //falls on a weekday
   if (now.getHours() > 9 && (now.getHours() < 17 && now.getMinutes() < 30)) {
      //it's in schedule
   }
}