How to pass data to javascript in Django Framework ?

28 July 2024

1

Django is a python framework for web development which works on jinja2 templating engine. When data is rendered along with the template after passing through views.py, that data becomes static on the html file along which it was rendered. As django is a backend framework, hence to use the power of python to use that data dynamically requests need to be generated. These requests can be type GET, POST, AJAX etc. But without making any call to the backend the only way to use that data dynamically is to pass it to JavaScript. Often passing a few values to JavaScript does the trick. But sometimes the entire dictionary of data needs to passed. This can be done using JSON and django template tags.

To check more about django framework in python visit – Django Tutorial.

In ‘views.py’ file –

from django.shortcuts import render
from json import dumps
  
  
def send_dictionary(request):
    # create data dictionary
    dataDictionary = {
        'hello': 'World',
        'Lazyroar': 'forLazyroar',
        'ABC': 123,
        456: 'abc',
        14000605: 1,
        'list': ['Lazyroar', 4, 'Lazyroar'],
        'dictionary': {'you': 'can', 'send': 'anything', 3: 1}
    }
    # dump data
    dataJSON = dumps(dataDictionary)
    return render(request, 'main / landing.html', {'data': dataJSON})

In ‘landing.html’ file –

<!DOCTYPE html>
<body>
    <div style="width: 40%;
    border: 1px solid black;
    background-color: lightcyan;
    font-family: Helvetica, sans-serif;">
        <div style="margin: 5%;">
            <h1>
                <u>Dictionary Data</u>
            </h1>
            <h2>
                <u>All Data</u>
            </h2>
            <h4 id='alldata'></h4><br>
            <h2>
                <u>Neat Data</u>
            </h2>
            <h4 id='neatdata'></h4>
        </div>
    </div>
</body>
</html>
<script>
    var data = JSON.parse("{{data|escapejs}}");
    var dataNode = document.getElementById('alldata');
    dataNode.innerHTML+="{{data|escapejs}}";
    dataNode = document.getElementById('neatdata');
    for(var x in data){
        dataNode.innerHTML+=x+' : '+data[x]+'<br><br>';
    }
</script>

Output:

Now, the value of “dictionary” is not the same as we entered in python. This is because JavaScript considers dictionaries as separate objects so to view the data of those objects we have to specify separately in JavaScript.

Use Case –

Let’s create an opposite finder website using Django. We will feed the opposite relation between words to Python and send it to JavaScript to determine the output based on user’s input.

In ‘views.py’ file –

from django.shortcuts import render
from json import dumps
  
  
def opposites(request):
    # create data dictionary
    data = [
        ["Laugh", "Cry"],
        ["Even", "Odd"],
        ["Hot", "Cold"],
        ["Light", "Dark"],
        ["Opposite", "Same"],
        ["Far", "Near"],
        ["Give", "Take"],
        ["Night", "Day"],
        ["Import", "Export"],
        ["Hard", "Easy"],
        ["Never", "Always"],
        ["Late", "Early"],
        ["Less", "More"],
        ["Male", "Female"],
        ["Happiness", "Sadness"],
        ["Fast", "Slow"],
        ["Old", "Young"],
        ["Boy", "Girl"],
        ["Up", "Down"],
        ["Left", "Right"],
        ["Rich", "Poor"],
        ["Love", "Hate"],
        ["Inside", "Outside"],
        ["Bad", "Good"],
        ["Short", "Tall"],
    ]
    data = dumps(data)
    return render(request, "main/opposites.html", {"data": data})

In ‘opposites.html’ file –

<!DOCTYPE html>
<html>
<body>
<div>
  Opposite of ?
  <input type="text" id="input" placeholder="Input">
  <input type="submit" id='opp' value="Submit" onclick="opposite()">
  <br><br>Result : <h id='result'></h>
</div>
</body>
</html>
<script>
  function opposite(){
    var data = JSON.parse("{{data|escapejs}}");
    var input = document.getElementById("input").value;
    var result = document.getElementById("result")
    var flag = 1;
    for(var x in data){
      if(input.toLowerCase()==data[x][0].toLowerCase()){
        result.innerHTML = data[x][1];
        flag=0;
      }
      else if(input.toLowerCase()==data[x][1].toLowerCase()){
        result.innerHTML = data[x][0];
        flag=0;
      }
    }
    if(flag){
      result.innerHTML = "No results found"
    }
  }
</script>