JS determines whether form input is empty

Source: Internet
Author: User
Tags trim

  This article is mainly on the JS to determine whether the form input is empty sample code is introduced, the need for friends can come to the reference, I hope to help you.

  Code below://Remove space   function trim on both sides of the input string (s) {      var count = s.length;       var St    = 0;      //start       var end   = count-1; End         IF (s = = "") return s;       while (St < count) {        if (S.charat (ST) = "")    & nbsp      st + +;         else          break;      &nbsp       while (End > St) {        if S.charat ( end) = = "")           end--;         else          break;      &nbsp       return s.substring (st,end + 1);     }      If the form is like this: The   code is as follows: <form action= "testnew.html" Name= "Form1" >  & nbSp     Username: <input type= "text" name= "name" >        Password: <input type= "Passwo Rd "Name=" pwd ">   <br>        <input type=" Submit "value=" submitted "onclick=" IsEmpty () "" & Gt      </form>     to determine if the input is empty you can define functions:  code as follows: Function IsEmpty () {     &N Bsp Form1 is the name attribute in form        var _form = Document.form1;          if (trim (_form.name.value) = "") {           alert ("" User name cannot be empty! ");                    return false;       }        if (trim (_form.pwd.value) = "") {         & nbsp Alert ("Password cannot be empty!");                   return false;       }         return true;  }      
Related Article

E-Commerce Solutions

Leverage the same tools powering the Alibaba Ecosystem

Learn more >

Apsara Conference 2019

The Rise of Data Intelligence, September 25th - 27th, Hangzhou, China

Learn more >

Alibaba Cloud Free Trial

Learn and experience the power of Alibaba Cloud with a free trial worth $300-1200 USD

Learn more >

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.