Author: John Au-Yeung

Sometimes, we want to define a JavaScript long integer.

In this article, we’ll look at how to define a JavaScript long integer.

How to define a JavaScript long integer?

To define a JavaScript long integer, we can define a bigint.

For instance, we write

const rem = bigInt("1738141852226360940").mod("32").valueOf();
console.log(rem);

to call the bigInt function with a string with the integer we want to define.

Then we call mod to return the modulo of the bigint when divided by 32.

And then we call valueOf to convert the returned value to an integer.

Conclusion

To define a JavaScript long integer, we can define a bigint.

Sometimes, we want to encode a query string so that it is the value of another query string in JavaScript.

In this article, we’ll look at how to encode a query string so that it is the value of another query string in JavaScript.

How to encode a query string so that it is the value of another query string in JavaScript?

To encode a query string so that it is the value of another query string in JavaScript, we use the encodeURIComponent function.

For instance, we write

const c = "d e";
const query = "?a=b&c=" + encodeURIComponent(c);
const uri = "http://www.example.com/script?query=" + encodeURIComponent(query);

to call encodeURIComponent with c to return a URL encoded version of string c.

Then we append that to the "http://www.example.com/script?query=".

Conclusion

To encode a query string so that it is the value of another query string in JavaScript, we use the encodeURIComponent function.

Sometimes, we want to get HTML "data-" attribute value with JavaScript.

In this article, we’ll look at how to get HTML "data-" attribute value with JavaScript.

How to get HTML "data-" attribute value with JavaScript?

To get HTML "data-" attribute value with JavaScript, we use the getAttribute method.

For instance, we write

const one = obj.getAttribute("data-uid");

to call getAttribute on element obj to get the value of the data-uid attribute.

Conclusion

To get HTML "data-" attribute value with JavaScript, we use the getAttribute method.

Sometimes, we want to get value of input type file with JavaScript.

In this article, we’ll look at how to get value of input type file with JavaScript.

How to get value of input type file with JavaScript?

To get value of input type file with JavaScript, we use the files property.

For instance, we write

const file = document.forms["formName"]["inputName"].files[0];

to get the file input with name attribute inputName in the form with name attribute formName with document.forms["formName"]["inputName"].

Then we get the selected files from the files property.

And we get the first file selected with index 0.

Conclusion

To get value of input type file with JavaScript, we use the files property.