I have a form with many input
$("input[name='firstname']")
Return
Object { 0: input.form-control, 1: input.form-control, 2: input.form-control, 3: input.form-control, length: 4, prevObject: {…} }
I search to set a value to the input, so I tried
$("input[name='firstname']")[0].val=12;
$("input[name='firstname']")[0].text=12;
I don't see the value in the input.
So I tried
$("input[name='firstname']")[0].val("12");
Uncaught TypeError: $(...)[0].val is not a function
The jQuery function $(selector) returns a jQuery object which acts somewhat like a collection of native elements.
When accessing indexed properties like [0], it returns the native HTMLElement.
If you want to just access the first matched element within the object but still have it be a jQuery object, use .eq(). The .val() method lets you safely set the value.
$("input[name=firstname]").eq(0).val(12)
Alternately, don't use jQuery at all
// querySelector returns the first match or null
const firstName = document.querySelector("input[name=firstname]");
if (firstName) {
firstName.value = 12;
}