jQuery：如何仅在Keydown事件上验证HTML5输入类型编号的键输入浮点值

Question

I am validating the form with HTML5 tag, input type number and I want to keep key validating for float value only when the user input the value in box. But I cannot get the correct value since I design the form with input type number and I input the value "12." I will get the value as "12" and if I type "12.." I will get value as empty string(""), actually the input should not allow to type "12..". So is there any possible way to make the key press validation for this?

Answer 1

In HTML5, the number type has a step value, max and min proprieties that validate it when submitted. The setp value also used by implementations for the stepper buttons (ie pressing up increases by step).

Step can be a float:

<input type="number" step="0.01">

For additional info read this blog post: http://blog.isotoma.com/2012/03/html5-input-typenumber-and-decimalsfloats-in-chrome/

But if you want to do it with jQuery you have to implement it yourself, by capturing the event and checking the entered data against your rules.

NB : As @artm commented, except for IE 8/9 and Opera Mini, this HTML5 feature is present across the rest of major browsers.