Chart js doesn't show chart
<p>i try to display only the example from chart js  in a project i work on. Unfortunately i'm forced to use Chart Js 1.x. 
I tried to implement the bar example from <a href="https://github.com/chartjs/Chart.js/blob/master/samples/bar/bar.html" rel="nofollow noreferrer">https://github.com/chartjs/Chart.js/blob/master/samples/bar/bar.html</a>
It's a pretty easy example i guess but it isn't running :(</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/1.1.1/Chart.js"&gt;&lt;/script&gt;
&lt;script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"&gt;&lt;/script&gt;

&lt;canvas id="zeitsteuerungChart"&gt;&lt;/canvas&gt;</code></pre>
</div>
</div>
</p>

<pre class="lang-js prettyprint-override"><code>var barChartData = {
        labels: ["January", "February", "March", "April", "May", "June", "July"],
        datasets: [{
            label: 'Dataset 1',
            borderWidth: 1,
            data: [
                "1","1","1","1","1","1","1"
            ]
        }, {
            label: 'Dataset 2',
            borderWidth: 1,
            data: [
                "1","1","1","1","1","1","1"
            ]
        }]
    };
    window.onload = function() {
        var ctx = document.getElementById("zeitsteuerungChart").getContext("2d");
        var myBar = new Chart(ctx, {
            type: 'bar',
            data: barChartData
        });
    };
</code></pre>

<p>The Chart JS manipulate the </p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;canvas id="zeitsteuerungChart"&gt;&lt;/canvas&gt;</code></pre>
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</div>
</p>

<p>element to </p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;canvas id="zeitsteuerungChart" width="300" height="150" style="width: 300px; height: 150px;"&gt;&lt;/canvas&gt;</code></pre>
</div>
</div>
</p>

<p>but thats  pretty much it. No diagram shows up. No error in Console. I tried to use jQuery as well to select the canvas with</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>var ctx = $("#zeitsteuerungChart").get(0).getContext("2d");</code></pre>
</div>
</div>
</p>

<p>but same effect! On other subpages of the project it's working pretty fine!</p>