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[英]'Uncaught SyntaxError: Unexpected token <' in Node.js
[英]Uncaught SyntaxError: Unexpected token var Node.js
我正在使用Node.js,并试图显示图表,该图表是根据txt文件的坐标生成的,并已上传到服务器。 我的问题:打开网页并上传文件时,一切正常,但是图表却无法正常工作:我收到以下错误: UncaughtSyntaxError:意外的令牌var。
如果我在不使用node.js的情况下呈现网页,则一切正常。
编码:
var express = require("express");
var app = express();
var fs = require('fs'); // we will need it for file uploads
var port = process.env.PORT || 3000;
app.configure(function(){
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(app.router);
app.use(express.static(__dirname + '/public'));
});
app.get('/', function(req, res) {
res.send('<form method="post" enctype="multipart/form-data">'
+ '<p>Image: <input type="file" name="uploadfile" /></p>'
+ '<p><input type="submit" value="Upload" /></p>'
+ '</form>');
});
app.post('/', function(req, res){
// .. Upload and file reading
// .. var obj[key1] (X-Values) and var obj[key2] (Y-Values) are generated
// ..
res.send('<head><title>Line Chart</title><script src="../Chart.js"></script><meta name = "viewport" content = "initial-scale = 1, user-scalable = no"><style>canvas{ }</style></head><body><canvas id="canvas" height="450" width="600"></canvas>'
+'<script type="text/javascript">'
+' '
+'var lineChartData = { '
+'labels : [ ' + obj[key1] + ' ],'
+'datasets : [{'
+'fillColor : "rgba(151,187,205,0.5)",'
+'strokeColor : "rgba(0, 0, 0, 0.831373)",'
+'pointColor : "rgba(151,187,205,1)",'
+'pointStrokeColor : "gba(76, 255, 178, 0.831373)",'
+'data : ['+ obj[key2] + ' ]'
+'} ] } '
+'var myLine = new Chart(document.getElementById("canvas").getContext("2d")).Line(lineChartData);'
+'</script>'
+'</body></html>'
);
};
});
});
});
app.listen(port, function() {
console.log("Listening on " + port);
});
我希望你能帮帮我..
问候,
JS
由于您不在代码示例中使用换行符,因此将输出:
var lineChartData = { labels : [ undefined ],datasets : [{fillColor : "rgba(151,187,205,0.5)",strokeColor : "rgba(0, 0, 0, 0.831373)",pointColor : "rgba(151,187,205,1)",pointStrokeColor : "gba(76, 255, 178, 0.831373)",data : [undefined ]} ] } var myLine = new Chart(document.getElementById("canvas").getContext("2d")).Line(lineChartData);
这是无效的Javascript,因为您需要使用;来关闭'lineChardData'对象。
将其更改为此,它将起作用:
res.send('<head><title>Line Chart</title><script src="../Chart.js"></script><meta name = "viewport" content = "initial-scale = 1, user-scalable = no"><style>canvas{ }</style></head><body><canvas id="canvas" height="450" width="600"></canvas>'
+'<script type="text/javascript">'
+' '
+'var lineChartData = { '
+'labels : [ ' + obj[key1] + ' ],'
+'datasets : [{'
+'fillColor : "rgba(151,187,205,0.5)",'
+'strokeColor : "rgba(0, 0, 0, 0.831373)",'
+'pointColor : "rgba(151,187,205,1)",'
+'pointStrokeColor : "gba(76, 255, 178, 0.831373)",'
+'data : ['+ obj[key2] + ' ]'
+'} ] }; '
+'var myLine = new Chart(document.getElementById("canvas").getContext("2d")).Line(lineChartData);'
+'</script>'
+'</body></html>'
);
同样,我也不认为以这种方式直接从Node.js输出HTML / javascript数据是一个好方法。
您没有发送任何换行符,因此(已精简)JavaScript解释器会看到以下无效代码:
var lineChartData = { /*...*/} var myLine = new Chart(/*...*/);
在第一个var
语句之后放一个分号,它将起作用:
var lineChartData = { /*...*/}; var myLine = new Chart(/*...*/);
// ^ Put me here
如果输出中出现换行符,则可以像ASI那样使用分号来工作,因此这是另一种可能的解决方案。
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