使用JavaScript添加一个OnClick事件

Question

I am trying to find a way to make classes that cause onclick events. So say for example in a form. I want to give that form field a class. Every time I add a certain class to a field I want it to generate an onclick command to the form field.

The reason I am doing this is I want to add analytic tracking to each form field, but I am using gravity forms so I want to be able to create forms on the fly without editing each one. If I could create a class called .name and have that class add this onClick="mixpanel.track('Name_field');" to the form input, then I could track everytime a user clicks inside the form to fill it out. This way I could track each step of the form and see when users leave.

So list would be

.name  that would add onClick="mixpanel.track('Name_field');"
.email  that would add onClick="mixpanel.track('Email_field');"
.phone  that would add onClick="mixpanel.track('pnone_field');"

I hope that makes sense. Thanks for any help you can give. I am fairly new to javascript so please be easy on me. html and css I am a pro but javascript is my next mountain to climb.

Answer 1

It would be far more efficient to delegate so you only have one event handler:

var f = function (e) {
  e = e || window.event;
  var t = e.srcElement || e.target, m;
  while (t !== this && (!t.className || !(m = t.className.match(/\b(name|email|phone)\b/)))) {
    t = t.parentNode;
  }
  if (m) {
    switch (m[0]) {
      case "name": mixpanel.track("Name_field"); break;
      case "email": mixpanel.track("Email_field"); break;
      case "phone": mixpanel.track("phone_field"); break;
    }
  }
};
if (document.body.attachEvent) {
  document.body.attachEvent("onclick", f, true);
} else {
  document.body.addEventListener("click", f, true);
}