To get the information from a meta tag with JavaScript, we use the content property.
For instance, we write
const content = document.head.querySelector(
"[property~=video][content]"
).content;
to select the meta element with the property attribute containing video and has the content attribute with document.head..querySelector from the head element.
Then we get the content attribute from the selected element with the content property.
To get the element clicked for the whole document with JavaScript, we add a click event handler for document.
For instance, we write
document.addEventListener(
"click",
(e) => {
const target = e.target;
const text = target.textContent;
},
false
);
to add a click handler for document with addEventListener.
In the click handler, we get the element that we clicked on with e.target.
And then we get the element’s text content with textContent.
To change the playing speed of videos in JavaScript, we set the defaultPlaybackRate and playbackRate properties.
For instance, we write
document.querySelector("video").defaultPlaybackRate = 2.0;
document.querySelector("video").play();
to select the video element with querySelector.
Then we set its default playback rate to 2 times the original speed by setting the defaultPlaybackRate property to 2.0.
Or we write
document.querySelector("video").playbackRate = 3.0;
to set the video’s playbackRate to 3 times the original speed.
To enable Bootstrap tooltip on disabled button with HTML, we wrap the disabled button with a wrapper element.
For instance, we write
<div class="tooltip-wrapper" data-title="hello world">
<button class="btn btn-default" disabled>button disabled</button>
</div>
to wrap a div with the data-title attribute with the tooltip text with class tooltip-wrapper around the disabled button to show the tooltip when hovering over the disabled button.
To create a string of variable length, filled with a repeated character with JavaScript, we call the array join method.
For instance, we write
const str = new Array(len + 1).join(character);
to create an array with length len + 1 with Array.
And then we call join with character to return a string filled with character of length len.