Category: JavaScript Answers

Sometimes, we want to convert a decimal string to a binary string with JavaScript.

In this article, we’ll look at how to convert a decimal string to a binary string with JavaScript.

How to convert a decimal string to a binary string with JavaScript?

To convert a decimal string to a binary string with JavaScript, we can use the JavaScript number’s toString method.

For instance, we write:

const num = '123'
const b = Number(num).toString(2)
console.log(b)

We call Number with num to convert num to a number.

Then we call toString on the returned number with 2 to convert it to a binary string.

As a result, b is '1111011'.

Conclusion

To convert a decimal string to a binary string with JavaScript, we can use the JavaScript number’s toString method.

Sometimes, we want to hide and show list items after the nth item with jQuery.

In this article, we’ll look at how to hide and show list items after the nth item with jQuery.

How to hide and show list items after the nth item with jQuery?

To hide and show list items after the nth item with jQuery, we can select the element after the nth item wit the gt selector and call show on them.

For instance, we write:

<ul>
  <li>One</li>
  <li>Two</li>
  <li>Three</li>
  <li>Four</li>
  <li>Five</li>
</ul>

<button class='showButton'>
  show
</button>

to add a button and a list.

Then we write:

$('ul li:gt(3)').hide();
$('.showButton').click(() => {
  $('ul li:gt(3)').show();
});

We select the li’s in the ul element that’s after the 3rd item with $('ul li:gt(3)').

Then we call hide on them to hide them.

And then we select the button with $('.showButton') and then call click on it with a callback that calls $('ul li:gt(3)').show(); to show the li’s after the 3rd item.

Conclusion

To hide and show list items after the nth item with jQuery, we can select the element after the nth item wit the gt selector and call show on them.

Sometimes, we want to make a button a file upload button with JavaScript.

In this article, we’ll look at how to make a button a file upload button with JavaScript.

How to make a button a file upload button with JavaScript?

To make a button a file upload button with JavaScript, we can create a hidden file input.

And then we add a button that opens the hidden file input when we click it.

For instance, we write:

<input id='fileid' type='file' hidden/>
<input id='buttonid' type='button' value='Upload MB' />

to add the hidden file input and a button.

Then we write:

const openDialog = () => {
  document.getElementById('fileid').click();
}

document.getElementById('buttonid').addEventListener('click', openDialog);

to add the openDialog function to select the hidden file input and call click on it to open the file selection dialog.

Then we select the button and call addEventListener on it to add openDialog as a click listener.

Conclusion

To make a button a file upload button with JavaScript, we can create a hidden file input.

And then we add a button that opens the hidden file input when we click it.

Sometimes, we want to compare JavaScript strings and get end difference.

In this article, we’ll look at how to compare JavaScript strings and get end difference.

How to compare JavaScript strings and get end difference?

To compare JavaScript strings and get end difference, we can use the JavaScript string’s split and join methods.

For instance, we write:

const a = "The quick brown fox"
const b = "The quick brown fox jumps over the lazy dog."

const diff = (diffMe, diffBy) => diffMe.split(diffBy).join('')

const c = diff(b, a)
console.log(c)

We create the diff function by calling split with diffBy and then calling join to join back the substring array returned by split.

Then we call diff with b and a to split b with a as the separator.

As a result, we get c, which is ' jumps over the lazy dog.'.

Conclusion

To compare JavaScript strings and get end difference, we can use the JavaScript string’s split and join methods.

Sometimes, we want to change div text with jQuery toggle.

In this article, we’ll look at how to change div text with jQuery toggle.

How to change div text with jQuery toggle?

To change div text with jQuery toggle, we can call the text method of an element.

For instance, we write:

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>

<div id="box">
  <div class="open">Show</div>
  <div class="showpanel">This is content</div>

  <div class="open2">Show</div>
  <div class="showpanel2">This is content</div>
</div>

to add some HTML elements.

Then we write:

$('.open').click(function() {
  const link = $(this);
  $('.showpanel').slideToggle('slow', function() {
    if ($(this).is(':visible')) {
      link.text('close');
    } else {
      link.text('open');
    }
  });
});

We select the divs with class open with $('.open').

Then we call click to add click handlers to them.

Next, we select the divs with class showpanel with $('.showpanel').

And then we call slidetoggle to add a slide toggle effect when we they’re shown or hidden from the screen.

In the event handler which is called when the animation is done, we call link.text to change the text of the link we selected earlier.

Conclusion

To change div text with jQuery toggle, we can call the text method of an element.