我在尝试使鼠标悬停在我的 D3 图形上时遇到问题（我不是 D3 专家）。我设法使线和点与缩放同步，但无法在点上方显示工具提示，不确定我是否遗漏了什么，如下图所示，一切正常。
你可以使用下面的按钮我的代码。谢谢您的帮助。
var data = JSON.parse('{"success":true,"response":[{"product_date":"2019-09-01","value":{"temperature":"30.6029968261719"}},{"product_date":"2019-09-02","value":{"temperature":"30.1170043945312"}},{"product_date":"2019-09-03","value":{"temperature":"30.0830078125"}},{"product_date":"2019-09-04","value":{"temperature":"30.2479858398438"}},{"product_date":"2019-09-05","value":{"temperature":"30.9110107421875"}},{"product_date":"2019-09-06","value":{"temperature":"31.3150024414062"}},{"product_date":"2019-09-07","value":{"temperature":"31.2909851074219"}},{"product_date":"2019-09-08","value":{"temperature":"30.7149963378906"}},{"product_date":"2019-09-09","value":{"temperature":"30.010009765625"}},{"product_date":"2019-09-10","value":{"temperature":"29.7990112304688"}},{"product_date":"2019-09-11","value":{"temperature":"29.6549987792969"}},{"product_date":"2019-09-12","value":{"temperature":"30.0769958496094"}},{"product_date":"2019-09-13","value":{"temperature":"30.0830078125"}},{"product_date":"2019-09-14","value":{"temperature":"29.8619995117188"}},{"product_date":"2019-09-15","value":{"temperature":"30.0029907226562"}},{"product_date":"2019-09-16","value":{"temperature":"30.1080017089844"}},{"product_date":"2019-09-17","value":{"temperature":"30.6979980469"}},{"product_date":"2019-09-18","value":{"temperature":"30.3139953613"}},{"product_date":"2019-09-19","value":{"temperature":"30.5180053710938"}},{"product_date":"2019-09-20","value":{"temperature":"30.3720092773"}},{"product_date":"2019-09-21","value":{"temperature":"29.8710021973"}},{"product_date":"2019-09-22","value":{"temperature":"29.7460021972656"}},{"product_date":"2019-09-23","value":{"temperature":"29.5769958496"}},{"product_date":"2019-09-24","value":{"temperature":"29.1159973145"}},{"product_date":"2019-09-25","value":{"temperature":"28.908996582"}}]}');
var svg = d3.select("svg"),
margin = {top: 20, right: 20, bottom: 110, left: 40},
margin2 = {top: 430, right: 20, bottom: 30, left: 40},
width = +svg.attr("width") - margin.left - margin.right,
height = +svg.attr("height") - margin.top - margin.bottom,
height2 = +svg.attr("height") - margin2.top - margin2.bottom;
var parseDate = d3.timeParse("%b %Y");
var x = d3.scaleTime().range([0, width]),
x2 = d3.scaleTime().range([0, width]),
y = d3.scaleLinear().range([height, 0]),
y2 = d3.scaleLinear().range([height2, 0]);
var xAxis = …d3.js ×1