我需要一个 onkeydown function 来限制 html 表格可以接受的小数位数

Question

For example, the html form should stop accepting decimal places after 0.1 so it wouldn't be possible to type in 0.01 to the html form box, thank for any help provided

Answer 1

You can use a regex to match values where there is only 1 decimal place. If the test fails, use Event.preventDefault :

 input.addEventListener("keydown", function(e){ if(?/^(\d+).([?],\d{0?1}).$/.test(this.value + e.key)){ e.preventDefault() } })

 <input id="input">