How to store data temporarily in java script from a html tag?

I am new to JavaScript and here is a challenge I don't know how to overcome!

Here is the sample code I tried:

<body>
    <p id="hello">Hello world.</p> 
    
    
    <script type="text/javascript">
    
    var store,newString,finalString;
    //i want to store the content of <p> tag in store variable
    store=?
    newString="I am Shuvrow";
    finalString = store + newString;
    //finally i want to replace the content of <p> tag by finalString variable
      
    </script>

</body>

Thanks

Solution

Use the innerHTML attribute of the document element, as such:

<body>
    <p id="hello">Hello world.</p> 
    
    
    <script type="text/javascript">
    
        var store,newString,finalString;

        // Get the contents of the element with the ID of 'hello' and assign it to the store variable.
        store = document.getElementById('hello').innerHTML;

        newString="I am Shuvrow";
        finalString = store + newString;

        // Replace the contents of the element with the ID of 'hello' with the value of the finalString variable.
        document.getElementById('hello').innerHTML = finalString;
    </script>

</body>