Trying to validate form

Question

Trying to learn JavaScript, makin decent progress I guess, but I'm stuck at validating a form, tried to see if anybody has the same problem, search didn't turn anything up. So would you please help me?

    var minlength = 6;
var pwlength = document.getElementById('psswrd');
var invalid = " ";

function validate() {

    if (pwlength.length < minlength && pwlength == invalid) {
        alert("Password not valid");

    else { 
        alert("Password okay!");
    }
}

submitbtn.onClick = validate();

it should be `var pwlength = document.getElementById('psswrd').value;` — Uttara, Aug 11 '12 at 06:45
better `var pwlength = document.getElementById('psswrd').value.length` — mplungjan, Aug 11 '12 at 07:06

score 1 · Accepted Answer · edited May 23 '17 at 10:24

It is not obvious where you call this - I have wrapped it in a window.onload
you do not access the button correctly. Either of document.forms[0].submitbtn document.getElementById("submitbtn") or document.getElementsByName("submitbtn")[0] will work depending on how you name or ID the button HOWEVER do not assign onclick handlers to submit buttons, instead assign submit handler to the form
there is no point of testing for a single space since that is less than 6 chars anyway.
&& is AND, you mean || OR
onclick must be all lowercase.
You assign the onclick to the result of validate instead of validate
You do not stop the submission

I have taken the trim from here and I assume the form has ID="form1"

window.onload=function()
  document.getElementById("form1").onsubmit = validate;
}

if(typeof String.prototype.trim !== 'function') { // let's help older IEs
  String.prototype.trim = function() {
    return this.replace(/^\s+|\s+$/g, ''); 
  }
}

function validate() {
  var minlength = 6;
  var pw = document.getElementById('psswrd');
  if (pw.value.length < minlength || pw.value.trim() == "") {
    alert("Password not valid");
    pw.focus();
    return false;
  }
  return true; // allow submission  
}

Your variable `pwlength` should always be `0`. Instead, the declaration of `pwval` should be before `pwlength` and the value of `pwlength` should equal `pwval.length`. Of course, with such little lifetimes, do you actually see a need to define variables to such things? — jeremy, Aug 11 '12 at 06:58
Great - took a while to find all the problems too. Good luck with your JS studies — mplungjan, Aug 11 '12 at 07:28

score 0 · Answer 2 · edited Aug 11 '12 at 06:48

0

var minlength = 6;

var pwlength = document.getElementById('psswrd');

var invalid = " ";

function validate() {

    if (pwlength.length < minlength && pwlength == invalid) {
        alert("Password not valid");
}

    else { 
        alert("Password okay!");
    }
}

edited Aug 11 '12 at 06:48

mplungjan

169,008
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answered Aug 11 '12 at 06:45

zeynal

1
1

This code will not work - you are not accessing the value of the field – mplungjan Aug 11 '12 at 07:11

score 0 · Answer 3 · answered Aug 11 '12 at 06:51

You have a few problems here.

1) pwlength.length won't get you very far. pwlength is equal to an html object, not the value of an html object. Change the actual variable to the following and you should get the correct results:

var pwlength = document.getElementById('psswrd').value;

2) Before the else part of your if ... else statement, you need to end the if statement by closing it with a curly bracket (}). Change that part to the following:

} else {

3) Your validation to check and see if the length == invalid is odd. Double check that and get rid of it.

4) Your onclick event needs to look something like this:

submitbtn.onclick = function(){ validate() };

Notice: lowercase event keyword and function() { ... }; wrapped around the function you want to run.

Actually looking at the var name, I would suggest `var pwlength = document.getElementById('psswrd').value.length` — mplungjan, Aug 11 '12 at 07:07

Trying to validate form

3 Answers3