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[英]Console error saying variable not defined, even though defined in same function
[英]Why is the JavaScript console saying my variable is undefined, even when I defined it two lines before?
我正在使用WebSockets连接到远程主机,每当我填充realData
并将其传递给grapher()
,JavaScript控制台都会告诉我realData
是未定义的。 我尝试检查数组中数据的类型,但这似乎很好。 在使用带有随机数据的数组之前,我已经调用了grapher()
,并且该调用顺利进行了。 但是,使用来自WebSocket的数据,该调用将始终给我“错误:未定义realData”。 我不确定为什么会这样。 这是我使用的代码:
current.html:
var command = "Hi Scott"
getData();
function getData()
{
console.log("getData is called");
if("WebSocket" in window)
{
var dataCollector = new WebSocket("ws://console.sb2.orbit-lab.org:6100",'binary');
dataCollector.binaryType = "arraybuffer";
console.log(dataCollector.readyState);
dataCollector.onopen = function()
{
//alert("The WebSocket is now open!");
console.log("Ready state in onopen is: " + dataCollector.readyState);
dataCollector.send(command);
console.log(command + " sent");
}
dataCollector.onmessage = function(evt)
{
console.log("onmessage is being called");
var realData = new Uint8Array(evt.data);
console.log(realData);
grapher(realData); //everything up to this point works perfectly.
}
dataCollector.onclose = function()
{
alert("Connection to Server has been closed");
}
return (dataCollector);
}
else
{
alert("Your browser does not support WebSockets!");
}
}
graphing.js:
function grapher(realData)
{
console.log("grapher is called");
setInterval('myGraph(realData);',1000); //This is where the error is. I always get "realData is not defined".
}
function myGraph(realData)
{
/*
for(var i = 0; i < SAarray.length; i++) // Loop which will load the channel data from the SA objects into the data array for graphing.
{
var data[i] = SAarray[i];
}
*/
console.log("myGraph is called");
var bar = new RGraph.Bar('channelStatus', realData);
bar.Set('labels', ['1','2','3','4','5','6','7','8']);
bar.Set('gutter.left', 50);
bar.Set('gutter.bottom', 40);
bar.Set('ymax',100);
bar.Set('ymin',0);
bar.Set('scale.decimals',1);
bar.Set('title','Channel Status');
bar.Set('title.yaxis','Status (1 is on, 0 is off)');
bar.Set('title.xaxis','Channel Number');
bar.Set('title.xaxis.pos',.1);
bar.Set('background.color','white');
bar.Set('colors', ['Gradient(#a33:red)']);
bar.Set('colors', ['red']);
bar.Set('key',['Occupied','Unoccupied']);
bar.getShapeByX(2).Set('colors',barColor(data[0]));
bar.Draw();
}
由于传递给setInterval
字符串(作为代码)在全局范围内执行,因此realData
参数不可用。 很少有理由将字符串传递给setInterval
。 而是使用:
setInterval(function () {
myGraph(realData);
}, 1000);
参考:
尝试它而不需要评估字符串:
setInterval(function() {
myGraph(realData);
},1000);
任何时候使用setTimeout
或setInterval
,都应该选择传递实际函数而不是字符串。
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