onclick in php echo with error invalid unexpected token

Question

I\'m trying to add the onclick funtion when user checked the check box, and then the total price will be shown.
All the information including price is retrieve from databas

Answer 1

Don't inline the event handler!

Also getElementsByName is plural and returns a collection:

document.getElementsByName("total")[0].value

Remove the inline event and instead use

//calculate price
function total() {
  var cal = document.getElementsByName('event[]');
  var total = 0;
  for (var i = 0; i < cal.length; i++) {
    if (cal[i].checked) {
      total += parseFloat(cal[i].getAttribute("data-price"));
    }
  }
  document.getElementsByName("total")[0].value = "$" + total.toFixed(2);
}
var checks = document.getElementsByName('event[]');
for (var i = 0; i < checks.length; i++) checks[i].onclick = total;

If you do not use total anywhere else, do

var checks = document.getElementsByName('event[]');
for (var i = 0; i < checks.length; i++) checks[i].onclick = function() {
  var cal = document.getElementsByName('event[]');
  var total = 0;
  for (var i = 0; i < cal.length; i++) {
    if (cal[i].checked) {
      total += parseFloat(cal[i].getAttribute("data-price"));
    }
  }
  document.getElementsByName("total")[0].value = "$" + total.toFixed(2);
}

var checks = document.getElementsByName('event[]');
for (var i = 0; i < checks.length; i++) checks[i].onclick = function() {
  var cal = document.getElementsByName('event[]');
  var total = 0;
  for (var i = 0; i < cal.length; i++) {
    if (cal[i].checked) {
      total += parseFloat(cal[i].getAttribute("data-price"));
    }
  }
  document.getElementsByName("total")[0].value = "$" + total.toFixed(2);
}

  title 1
  1-1-2018
  2-2-2018
  Event 1
  Place 1
  100
  


  title 2
  2-2-2018
  3-3-2018
  Event 2
  Place 2
  200
  


		
Total cost
		Total