https://www.frc.org/js/frc/custom_selects.js

1
2(function(){
3  var x, i, j, selElmnt, a, b, c;
4  /*look for any elements with the class "custom-select":*/
5  x = document.getElementsByClassName("custom-select");
6  for (i = 0; i < x.length; i++) {
7    selElmnt = x[i].getElementsByTagName("select")[0];
8    /*for each element, create a new DIV that will act as the selected item:*/
9    a = document.createElement("DIV");
10    a.setAttribute("class", "select-selected");
11    a.innerHTML = selElmnt.options[selElmnt.selectedIndex].innerHTML;
12    x[i].appendChild(a);
13    /*for each element, create a new DIV that will contain the option list:*/
14    b = document.createElement("DIV");
15    b.setAttribute("class", "select-items select-hide");
16    for (j = 1; j < selElmnt.length; j++) {
17      /*for each option in the original select element,
18      create a new DIV that will act as an option item:*/
19      c = document.createElement("DIV");
20      c.innerHTML = selElmnt.options[j].innerHTML;
21      c.addEventListener("click", function(e) {
22          /*when an item is clicked, update the original select box,
23          and the selected item:*/
24          var y, i, k, s, h;
25          s = this.parentNode.parentNode.getElementsByTagName("select")[0];
26          h = this.parentNode.previousSibling;
27          for (i = 0; i < s.length; i++) {
28            if (s.options[i].innerHTML == this.innerHTML) {
29              s.selectedIndex = i;
30              h.innerHTML = this.innerHTML;
31              y = this.parentNode.getElementsByClassName("same-as-selected");
32              for (k = 0; k < y.length; k++) {
33                y[k].removeAttribute("class");
34              }
35              this.setAttribute("class", "same-as-selected");
36              break;
37            }
38          }
39          h.click();
40      });
41      b.appendChild(c);
42    }
43    x[i].appendChild(b);
44    a.addEventListener("click", function(e) {
45        /*when the select box is clicked, close any other select boxes,
46        and open/close the current select box:*/
47        e.stopPropagation();
48        closeAllSelect(this);
49        this.nextSibling.classList.toggle("select-hide");
50        this.classList.toggle("select-arrow-active");
51      });
52  }
53  function closeAllSelect(elmnt) {
54    /*a function that will close all select boxes in the document,
55    except the current select box:*/
56    var x, y, i, arrNo = [];
57    x = document.getElementsByClassName("select-items");
58    y = document.getElementsByClassName("select-selected");
59    for (i = 0; i < y.length; i++) {
60      if (elmnt == y[i]) {
61        arrNo.push(i)
62      } else {
63        y[i].classList.remove("select-arrow-active");
64      }
65    }
66    for (i = 0; i < x.length; i++) {
67      if (arrNo.indexOf(i)) {
68        x[i].classList.add("select-hide");
69      }
70    }
71  }
72  /*if the user clicks anywhere outside the select box,
73  then close all select boxes:*/
74  document.addEventListener("click", closeAllSelect);
75}());