javascript - How to change Uptick Increments in HTML Number Input -

i have number input form:

<input type='number' id='select-number'>pick number 

i have following questions:

1: default uptick increment 1 (when click arrow on number input, goes value of 1 per click.) how can change that? want go in values of 0.1 (tenths). how do that?

2: secondly, have 2 variables:

feet=true; meters=false; 

one true, , other false. how change "max" attribute (using javascript) based on of these 2 variables true? 2 variables come code this:

<input type='radio' id='feet' name='unit_of_measurement'>feet <input type='radio' id='meters' name='unit_of_measurement'>meters <script> feet=document.getelementbyid('feet').checked; meters=document.getelementbyid('meters').checked; </script> 

if variable "feet" true, maximum value of input (id='select-number') needs 3. if meters, needs 8.

how can that(^), , how can change uptick increment? help.

note: vanilla javascript only, please

1) change step of input use step=".1" inside input tag.

2) change max on radio change add onchange="change()" sets max and/or step based on checked

html

<input type='radio' id='feet' name='unit_of_measurement' onchange="change()" checked>feet <input type='radio' id='meters' name='unit_of_measurement' onchange="change()">meters 

js

function change() {   feet = document.getelementbyid('feet').checked;   meters = document.getelementbyid('meters').checked;   selectnumber = document.getelementbyid('select-number');   if (feet) {       selectnumber.max = 300;       selectnumber.step = 1;   } else {       selectnumber.max = 100;       selectnumber.step = .3;   } }; 

fiddle or fiddle 2