Display stock quotes from Yahoo!: Difference between revisions

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The curve is updated only once a second, so initially it needs a little patience until the  
The curve is updated only once a second, so initially it needs a little patience until the  
curve is visible.
curve is visible.
Beware that in order to simplify the handling of AJAX we use the additional library [http://www.prototypejs.org/ prototype.js] in this example.


<html>
<html>
  <script type="text/javascript" src="https://jsxgraph.uni-bayreuth.de/distrib/prototype.js"></script>
   <form>
   <form>
     <input type="button" value="Start" onClick="Start()">  
     <input type="button" value="Start" onClick="Start()">  
Line 28: Line 31:
                 val = a[1];  // set the text
                 val = a[1];  // set the text
                 if (!g) {  
                 if (!g) {  
                     g = brd.createElement('curve', [x,y],{strokeWidth:3, strokeColor:'green',shadow:true});  
                    x[0] += 1; // for shadows of horizontal lines.
                     txt = brd.createElement('text', [3,(hi+lo)*0.5,function(){return 'GDAXI = '+val;}],{fontSize:'14px'});  
                     g = brd.create('curve', [x,y],{strokeWidth:3, strokeColor:'green',shadow:true});  
                     //brd.createElement('functiongraph',[JXG.Math.Numerics.regressionPolynomial(1,g.dataX,g.dataY)],{strokecolor:'red',dash:3});
                     txt = brd.create('text', [3,(hi+lo)*0.5,function(){return 'GDAXI = '+val;}],{fontSize:14});  
                     brd.create('functiongraph',[JXG.Math.Numerics.regressionPolynomial(1,g.dataX,g.dataY)],{strokecolor:'red',dash:3});
                 } else {
                 } else {
                     g.dataX = x;                     
                     g.dataX = x;                     
Line 50: Line 54:
                 lo = a[7]*0.99998;
                 lo = a[7]*0.99998;
                 brd = JXG.JSXGraph.initBoard('jxgbox', {axis:true, boundingbox:[0,hi,200,lo]});
                 brd = JXG.JSXGraph.initBoard('jxgbox', {axis:true, boundingbox:[0,hi,200,lo]});
                 brd.createElement('axis',[[0,lo],[1,lo]]);
                 brd.create('axis',[[0,lo],[1,lo]]);
                 Start();
                 Start();
             };
             };
Line 72: Line 76:
<html><div id="debug"></div></html>
<html><div id="debug"></div></html>
===The underlying JavaScript code===
===The underlying JavaScript code===
<source lang="xml">
<source lang="javascript">
<jsxgraph width="700" height="400">
var hi, lo, brd, periodical,  
var hi, lo, brd, periodical,  
     brd, g, txt, val,
     brd, g, txt, val,
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                 val = a[1];  // set the text
                 val = a[1];  // set the text
                 if (!g) {  
                 if (!g) {  
                     g = brd.createElement('curve', [x,y],{strokeWidth:3, strokeColor:'green',shadow:true});  
                     g = brd.create('curve', [x,y],{strokeWidth:3, strokeColor:'green',shadow:true});  
                     txt = brd.createElement('text', [3,(hi+lo)*0.5,function(){return 'GDAXI = '+val;}],{fontSize:'14px'});  
                     txt = brd.create('text', [3,(hi+lo)*0.5,function(){return 'GDAXI = '+val;}],{fontSize:14});  
                     brd.createElement('functiongraph',[JXG.Math.Numerics.regressionPolynomial(1,g.dataX,g.dataY)],{strokecolor:'red',dash:3});
                     brd.create('functiongraph',[JXG.Math.Numerics.regressionPolynomial(1,g.dataX,g.dataY)],{strokecolor:'red',dash:3});
                 } else {
                 } else {
                     g.dataX = x;                     
                     g.dataX = x;                     
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                 lo = a[7]*0.99998;
                 lo = a[7]*0.99998;
                 brd = JXG.JSXGraph.initBoard('jxgbox', {axis:true, boundingbox:[0,hi,200,lo]});
                 brd = JXG.JSXGraph.initBoard('jxgbox', {axis:true, boundingbox:[0,hi,200,lo]});
                 brd.createElement('axis',[[0,lo],[1,lo]]);
                 brd.create('axis',[[0,lo],[1,lo]]);
                 Start();
                 Start();
             };
             };
Line 131: Line 134:
   }
   }
};
};
</jsxgraph>


</source>
</source>
Line 139: Line 140:
<source lang="php">
<source lang="php">
<?php
<?php
$fp = fopen ("http://finance.yahoo.com/d/quotes.csv?s=^gdaxi&f=sl1d1t1c1ohgv&e=.csv","r");
$fp = fopen ("https://finance.yahoo.com/d/quotes.csv?s=^gdaxi&f=sl1d1t1c1ohgv&e=.csv","r");
echo fgets ($fp, 1024);
echo fgets ($fp, 1024);
fclose ($fp);
fclose ($fp);

Latest revision as of 13:45, 10 March 2017

This JSXGraph application fetches the live stock quotes of the German DAX Index (gdaxi) from Yahoo!. The curve is updated only once a second, so initially it needs a little patience until the curve is visible.

Beware that in order to simplify the handling of AJAX we use the additional library prototype.js in this example.

The underlying JavaScript code

var hi, lo, brd, periodical, 
    brd, g, txt, val,
    x = [],
    y = [];


fetchData = function() {
    new Ajax.Request('/ajax/stockquotes.php', {
        onComplete: function(transport) {
            var t, a;
            if (200 == transport.status) {
                t = transport.responseText;
                a = t.split(',');
                x.push(x.length+1);
                y.push(a[1]);
                val = a[1];  // set the text
                if (!g) { 
                    g = brd.create('curve', [x,y],{strokeWidth:3, strokeColor:'green',shadow:true}); 
                    txt = brd.create('text', [3,(hi+lo)*0.5,function(){return 'GDAXI = '+val;}],{fontSize:14}); 
                    brd.create('functiongraph',[JXG.Math.Numerics.regressionPolynomial(1,g.dataX,g.dataY)],{strokecolor:'red',dash:3});
                } else {
                    g.dataX = x;                    
                    g.dataY = y;
                }
                brd.update();
            };
    }});
};

// Fetch max and min, and start the periodical update.
new Ajax.Request('/ajax/stockquotes.php', {
        onComplete: function(transport) {
            var a, t;
            if (200 == transport.status) {
                t = transport.responseText;
                a = t.split(',');
                hi = a[6]*1.00002;
                lo = a[7]*0.99998;
                brd = JXG.JSXGraph.initBoard('jxgbox', {axis:true, boundingbox:[0,hi,200,lo]});
                brd.create('axis',[[0,lo],[1,lo]]);
                Start();
            };
    }});


Start = function() {
   if (periodical==null) {
      periodical = setInterval(fetchData,1000);  // Start the periodical update
   }
};

Stop = function() {
   if (periodical!=null) {
       clearInterval(periodical);
       periodical = null;
   }
};

The PHP code

<?php
$fp = fopen ("https://finance.yahoo.com/d/quotes.csv?s=^gdaxi&f=sl1d1t1c1ohgv&e=.csv","r");
echo fgets ($fp, 1024);
fclose ($fp);
?>