<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
<div id = "selectbox"> </div>
<div id = "chart1"> </div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script src = "https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.3/js/bootstrap.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.5.0/d3.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/crossfilter/1.3.12/crossfilter.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/dc/3.0.6/dc.min.js"></script>
<script>
var facts = crossfilter([
{"Period":"Jan-18","Department":"Dept 1","Percentage":0.2098},
{"Period":"Feb-18","Department":"Dept 1","Percentage":0.6058},
{"Period":"Mar-18","Department":"Dept 1","Percentage":0.691},
{"Period":"Jan-18","Department":"Dept 2","Percentage":0.2705},
{"Period":"Feb-18","Department":"Dept 2","Percentage":0.4113},
{"Period":"Mar-18","Department":"Dept 2","Percentage":0.3698},
{"Period":"Jan-18","Department":"Dept 3","Percentage":0.3239},
{"Period":"Feb-18","Department":"Dept 3","Percentage":0.4638},
{"Period":"Mar-18","Department":"Dept 3","Percentage":0.4036},
{"Period":"Jan-18","Department":"Dept 4","Percentage":0.8288},
{"Period":"Feb-18","Department":"Dept 4","Percentage":0.0809},
{"Period":"Mar-18","Department":"Dept 4","Percentage":0.9152},
{"Period":"Jan-18","Department":"All","Percentage":0.6104},
{"Period":"Feb-18","Department":"All","Percentage":0.3348},
{"Period":"Mar-18","Department":"All","Percentage":0.8257},
])
var PeriodDimension = facts.dimension( function (d) {return d.Period} );
var DeptDimension = facts.dimension( function (d) {return d.Department} );
dc.selectMenu("#selectbox")
.dimension(DeptDimension)
.group(DeptDimension.group())
.promptText("removethisline")
.controlsUseVisibility(true);
dc.renderAll();
</script>
</body>
两个问题
1）如果您在JSFiddle中注意到，我们会在下拉列表中获得键和值。我们只需要键，即在下拉菜单中只需要All，Dept 1，Dept 2等。
2）由于我已经有一个内置数据的“全部”选项，如何从下拉菜单中删除hintText值？