EJS逻辑有效，但html未显示

Question

I'm working on a timer using Express.js and EJS. I'm trying to update the html dynamically but i don't get anything displayed. But i get the console.log in my cli.

 <div id="countdown"> <% setInterval(function(){ %> <% var now = new Date().getTime(); %> <% var distance = expiration - now; %> <% var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60)); %> <% var seconds = Math.floor((distance % (1000 * 60)) / 1000); %> <% if (distance > 0 ) { %> <% console.log(minutes + ':' + seconds) %> <p>This isn't showing</p> <% } else { %> <% console.log('expired') %> <p>This isn't showing</p> <% }; %> <% }, 1000); %> </div> 

CLI Am i missing something obvious?

I have other dynamic tags as <h2>Send <%= displayAmount %> to:</h2> but they aren't working inside the conditional.

Answer 1

The problem is that the JavaScript keeps running, as you have programmed it to do, but the page is not re-rendering, because it is only told to render once.

You would have to write another JavaScript function that will re-render the DOM every iteration.

Something like:

let myDiv = document.getElementById('countdown');

// Delete previously added elements
while (myDiv.firstChild) {
  myDiv.removeChild(myDiv.firstChild);
}

// Create a <p>
let p = document.createElement('p');

// Create your text
let text = document.createTextNode(`${minutes}:${seconds}`);
// OR:
let text = document.createTextNode('Expired');

// Append the text to <p>
p.appendChild(text);

// Append the <p> to div
myDiv.appendChild(p);