JavaScript value of an empty form field
Question
I want to validate an HTML form to ensure an <input> has a value. In JavaScript, what is the value of an empty field in a form: null or the empty string ( "" )?
3 answers
solution1
3 ACCPTED 2011-04-29 18:21:32
For any input element, value is always a string. This means you can expect it to be "" , when empty.
See the docs for HTMLInputElement on the Mozilla Developer Network, or the relevant part of the HTML4 spec .
solution2
0 2011-04-29 18:21:43
Empty string, if it's a text field.
solution3
0 2011-04-29 18:21:58
It's an empty string -- one of the beautiful perks of JavaScript.
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.
Related Question
Javascript cannot submit form with empty field validation
Javascript - Form submits with required field left empty
javascript empty field form validation not working
javascript form validation for empty field and wrong input
validate form field for null or empty using javascript
change form field value with javascript
Javascript: Editing the Value of a Form Field?
insert javascript value into form field
Setting value to a form field with JavaScript
Set field value - only if empty - in a Marketo Form
Related Tags