图表在使用 d3.json(bardata.json) 时正常创建，但在使用 d3.json(bardata.php) 时出现空白网页(无图表)-- bardata.json 是 bardata.php 回显的输出文件
这是bardata.php文件
<?php
$username = "root";
$password = "nk";
$host = "localhost";
$database="homedb";
$server = mysql_connect($host, $username, $password);
$connection = mysql_select_db($database, $server);
$myquery = "
SELECT `date`, `value` FROM `bar_data`
";
$query = mysql_query($myquery);
if ( ! $query ) {
echo mysql_error();
die;
}
$data = array();
for ($x = 0; $x < mysql_num_rows($query); $x++) {
$data[] = mysql_fetch_assoc($query);
}
echo json_encode($data);
mysql_close($server);
?>
这是 bardata.json
[{"date":"2013-01","value":"53"},{"date":"2013-02","value":"165"},{"date":"2013-03","value":"269"},{"date":"2013-04","value":"344"},{"date":"2013-05","value":"376"},{"date":"2013-06","value":"410"},{"date":"2013-07","value":"421"},{"date":"2013-08","value":"405"},{"date":"2013-09","value":"376"},{"date":"2013-10","value":"359"},{"date":"2013-11","value":"392"},{"date":"2013-12","value":"433"},{"date":"2014-01","value":"455"},{"date":"2014-02","value":"478"}]
这是我的 index.html
<!DOCTYPE html>
<meta charset="utf-8">
<style> /* set the CSS */
body { font: 12px Arial;}
path {
stroke: steelblue;
stroke-width: 2;
fill: none;
}
.axis path,
.axis line {
fill: none;
stroke: grey;
stroke-width: 1;
shape-rendering: crispEdges;
}
</style>
<body>
<script src="http://d3js.org/d3.v3.js"></script>
<script>
var margin = {top: 20, right: 20, bottom: 70, left: 40},
width = 600 - margin.left - margin.right,
height = 300 - margin.top - margin.bottom;
// Parse the date / time
var parseDate = d3.time.format("%Y-%m").parse;
var x = d3.scale.ordinal().rangeRoundBands([0, width], .05);
var y = d3.scale.linear().range([height, 0]);
var xAxis = d3.svg.axis()
.scale(x)
.orient("bottom")
.tickFormat(d3.time.format("%Y-%m"));
var yAxis = d3.svg.axis()
.scale(y)
.orient("left")
.ticks(10);
var svg = d3.select("body").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform",
"translate(" + margin.left + "," + margin.top + ")");
//getting blank web browser when passing .php output
d3.json("bardata.php", function(error, data) {
if (error) return console.warn(error);
console.log(data);
data.forEach(function(d) {
d.date = parseDate(d.date);
d.value = +d.value;
});
//if I use .json than its working, the same .json which i get by echoing the bardata.php output
/*d3.json("bardata.json", function(error, data) {
if (error) return console.warn(error);
console.log(data);
data.forEach(function(d) {
d.date = parseDate(d.date);
d.value = +d.value;
});*/
x.domain(data.map(function(d) { return d.date; }));
y.domain([0, d3.max(data, function(d) { return d.value; })]);
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis)
.selectAll("text")
.style("text-anchor", "end")
.attr("dx", "-.8em")
.attr("dy", "-.55em")
.attr("transform", "rotate(-90)" );
svg.append("g")
.attr("class", "y axis")
.call(yAxis)
.append("text")
.attr("transform", "rotate(-90)")
.attr("y", 6)
.attr("dy", ".71em")
.style("text-anchor", "end")
.text("Value ($)");
svg.selectAll("bar")
.data(data)
.enter().append("rect")
.style("fill", "steelblue")
.attr("x", function(d) { return x(d.date); })
.attr("width", x.rangeBand())
.attr("y", function(d) { return y(d.value); })
.attr("height", function(d) { return height - y(d.value); });
});
</script>
</body>
我用的这个库对吗？或者我做错了什么？ ;所有文件 bardata.json、bardata.php、index.html 都在同一目录中。
当调试 firefox 浏览器时，在这一行出现这个错误， “如果(错误)返回控制台。警告(错误)；”
SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data
Stack trace:
d3_json@http://d3js.org/d3.v3.js:9488:12
respond@http://d3js.org/d3.v3.js:1939:20
我是 d3.js 的新手。谢谢。
最佳答案
在重新创建您的设置并对其进行测试后，它确实可以毫无问题地加载和创建条形图。我已经在 Chrome、Firefox、Edge、Safari 上对其进行了测试，它们都可以正常工作。检查编码以确保它是 UTF-8，以便 json_encode 确实选择数组。使用 d3.js 的本地副本进行测试。
关于javascript - 带有 d3.json(bardata.php) 的空白网页，但适用于 d3.json(bardata.json)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33417807/