Fill in a input field on a website with JavaScript if it has no id?

Question

How can I fill in a input field on a website with JavaScript if it has no id? Example:

<input type="text" placeholder="First Name" value="" class="someclass">
<input type="text" placeholder="Last Name" value="" class="someclass">

I only want to fill in the first input field.

If it had an ID I could just do document.getElementById... the class and type are used by several input fields on the website. Could I maybe use the placeholder somehow?

Answer 1

Simply select it with document.querySelector('input.someclass')

EDIT

If the order and amount of inputs is always the same on your website just do this:

const inputs = document.querySelectorAll('input')

You can choose the input from the array that querySelectorAll returns or loop through the array to input the values.

const inputs = document.querySelectorAll('input');
const valuesToInput = [1,2,3,4,5,6,7,8,9];
for(let i = 0; i < inputs.length; i += 1) {
   inputs[i].value = valuesToInput[i];
}