Line Chart Crosshairs

http://stackoverflow.com/questions/21417298/d3js-chart-with-crosshair-as-tooltip-how-to-add-2-lines-which-intersect-at-curs

HTML

<svg></svg>

CSS

.line {
	fill: none;
  stroke: green;
  stroke-width: 3px;
}

.area {
  fill: url(#temperature-gradient);
}

.overlay {
  fill: none;
  pointer-events: all;
}

.focus line {
  fill: none;
  stroke-width: 1.5;
  stroke: gray;
}

.focus text, line {
	opacity: 0.5;
}

JavaScript

var sample2 = [
    {"time": 1387212120, "open": 368, "close": 275, "high": 380, "low": 158},
    {"time": 1387212130, "open": 330, "close": 350, "high": 389, "low": 310},
    {"time": 1387212140, "open": 213, "close": 253, "high": 289, "low": 213},
    {"time": 1387212150, "open": 180, "close": 150, "high": 189, "low": 110},
    {"time": 1387212160, "open": 310, "close": 350, "high": 389, "low": 310},
    {"time": 1387212170, "open": 213, "close": 253, "high": 289, "low": 213},
    {"time": 1387212180, "open": 190, "close": 150, "high": 189, "low": 110},
    {"time": 1387212190, "open": 362, "close": 530, "high": 589, "low": 510},
    {"time": 1387212200, "open": 409, "close": 356, "high": 300, "low": 510},
    {"time": 1387212210, "open": 334, "close": 275, "high": 369, "low": 185},
    {"time": 1387212220, "open": 304, "close": 389, "high": 389, "low": 310},
    {"time": 1387212230, "open": 395, "close": 235, "high": 289, "low": 213},
    {"time": 1387212240, "open": 339, "close": 148, "high": 189, "low": 110},
    {"time": 1387212250, "open": 310, "close": 350, "high": 389, "low": 310},
    {"time": 1387212260, "open": 283, "close": 253, "high": 289, "low": 213},
    {"time": 1387212270, "open": 290, "close": 350, "high": 189, "low": 110},
    {"time": 1387212280, "open": 448, "close": 550, "high": 624, "low": 510},
    {"time": 1387212290, "open": 419, "close": 299, "high": 194, "low": 510},
    {"time": 1387212300, "open": 150, "close": 163, "high": 189, "low": 145},
    {"time": 1387212310, "open": 330, "close": 350, "high": 356, "low": 310},
    {"time": 1387212320, "open": 213, "close": 253, "high": 289, "low": 213},
    {"time": 1387212330, "open": 180, "close": 150, "high": 189, "low": 110},
    {"time": 1387212340, "open": 310, "close": 350, "high": 389, "low": 310},
    {"time": 1387212350, "open": 213, "close": 253, "high": 289, "low": 213},
    {"time": 1387212360, "open": 190, "close": 150, "high": 230, "low": 110},
    {"time": 1387212370,...