Category: JavaScript Answers

Sometimes, we want to disable all input buttons with JavaScript.

In this article, we’ll look at how to disable all input buttons with JavaScript.

How to disable all input buttons with JavaScript?

To disable all input buttons with JavaScript, we can select all the input elements and loop through them to set the disabled property of each to true.

For instance, we write:

<input type='button' value='button'>
<input type='button' value='button'>
<input type='button' value='button'>

to add a few input elements.

Then we write:

const inputs = document.getElementsByTagName("input");
for (const input of inputs) {
  input.disabled = true
}

to select all the inputs with getElementsByTagname.

Next, we loop through each input with the for-of loop.

In the loop body, we set the disabled property of each input to true to disable them.

Conclusion

To disable all input buttons with JavaScript, we can select all the input elements and loop through them to set the disabled property of each to true.

Sometimes, we want to return a substring from a string to the end using JavaScript.

In this article, we’ll look at how to return a substring from a string to the end using JavaScript.

How to return a substring from a string to the end using JavaScript?

To return a substring from a string to the end using JavaScript, we can use some string methods.

For instance, we write:

const strIn = 'http://localhost/40ATV/dashboard.php?page_id=projeto_lista&lista_tipo=equipe';
const searchTerm = '/dashboard.php?';
const searchIndex = strIn.indexOf(searchTerm);
const strOut = strIn.substr(searchIndex + searchTerm.length);
console.log(strOut)

to get substring from strIn after '/dashboard.php?'.

To do this, we get the index of the first character of searchTerm with strIn.indexOf(searchTerm).

Then we call strIn.substr with searchIndex + searchTerm.length to return a substring from strIn starting from index searchIndex + searchTerm.length + 1 to the end of the string.

Therefore, strOut is 'page_id=projeto_lista&lista_tipo=equipe '.

Conclusion

To return a substring from a string to the end using JavaScript, we can use some string methods.

Sometimes, we want to read in a local csv file in JavaScript.

In this article, we’ll look at how to read a csv file in JavaScript.

How read a csv file in JavaScript?

To read a csv file in JavaScript, we can use the FileReader constructor.

For instance, we write:

<input type="file">

to add a file input.

Then we write:

const input = document.querySelector('input')
const fileReader = new FileReader()
fileReader.onload = (e) => {
  console.log(e.target.result)
}

input.onchange = (e) => {
  const [file] = e.target.files
  fileReader.readAsBinaryString(file)
}

to select the input with querySelector.

Next, we create a FileReader instance.

Then we set its onload property to a function that logs the file content.

Next, we set input.onchange to a function that gets the selected file from e.target.files.

And then we call fileReader.readAsBinaryString to read the file.

Conclusion

To read in local csv file in JavaScript, we can use the FileReader constructor.

Sometimes, we want to loop over the child divs of a div and get the ids of the child divs with JavaScript.

In this article, we’ll look at how to loop over the child divs of a div and get the ids of the child divs with JavaScript.

How to loop over the child divs of a div and get the ids of the child divs with JavaScript?

To loop over the child divs of a div and get the ids of the child divs with JavaScript, we can use some DOM methods and the spread operator.

For instance, we write:

<div id="test">
  <div id="test-1"></div>
  <div id="test-2"></div>
  <div id="test-3"></div>
  <div id="test-4"></div>
</div>

to add a div with divs.

Then we write:

const childDivs = document.getElementById('test').getElementsByTagName('div');
const ids = [...childDivs].map(d => d.id)
console.log(ids)

to select all the child divs in the div with ID test with document.getElementById('test').getElementsByTagName('div').

Then we spread the returned node list into an array and call map with a callback to return the id attribute value from each div.

Therefore, ids is ["test-1", "test-2", "test-3", "test-4"].

Conclusion

To loop over the child divs of a div and get the ids of the child divs with JavaScript, we can use some DOM methods and the spread operator.

Sometimes, we want to assign a function to the property of a JavaScript object.

In this article, we’ll look at how to assign a function to the property of a JavaScript object.

How to assign a function to the property of a JavaScript object?

To assign a function to the property of a JavaScript object, we can use the assignment operator.

For instance, we write:

const obj = {}
obj.hello = () => {
  console.log('hello')
}
obj.hello()

to assign a function that logs 'hello' as the value of the obj.hello property.

Then we call the function with obj.hello().

Conclusion

To assign a function to the property of a JavaScript object, we can use the assignment operator.