What is the JavaScript code for validating a form, getting elements by name, with a loop?

Question

I have read between 5 & 7 posts, have tried to play with some of the things I have read, including jQuery, but it feels as though most posts are well beyond my understanding.

I have a form which will act as a data submission tool, so let's say 100 inputs.

I just need help checking each input, and I figured that I should be able to do it using a loop.

Goal code example:

function ()
{
    for (i = 1; i < 101 ; i++);
    var c = document.getElementsByName("Input_row_" [i]);
        if ( c = some conditionals here )
        {
            alert("message");
            return false;
            }
}

For a specific argument, one of the things I need to check is that there are no spaces in the input:

function ()
{
    for (i = 1; i < 101 ; i++);
    var c = document.getElementsByName("Input_row_" [i]);
        if ( c = "" )
        {
            alert("message");
            return false;
            }
}

Can anyone help with my syntax or get me further towards the goal?

Thanks.

-It goes without saying that I am not a programer by trade, so simple explanations would be great.

A few problems I see. Empty function name? Bad concatenation. Conditional with one equals. Global `i`... I think you need to start learning JS from scratch with a decent tutorial, check here http://jqfundamentals.com/chapter/javascript-basics — elclanrs, May 24 '13 at 04:34
Semicolon does not belong on the `for` line. Syntax errors galore. Check your browser console; step through your code with a debugger. — Matt Ball, May 24 '13 at 04:35
@elclanrs - Thanks for the tutorial resource, I obviously do need a structured progression of learning javaScript. — brian-welch, May 24 '13 at 06:17
@MattBall - Does Dreamweaver have adequate debugging in your estimation? — brian-welch, May 24 '13 at 06:18

mplungjan · Accepted Answer · 2013-05-24T04:39:21.430

Method 1

function validate() {
  for (var i = 1; i < 101 ; i++) {
    var c = document.getElementsByName("Input_row_"+i)[0].value;
    if (c == "" ) {
      alert("Please fill in #"+(i+1));
      return false;
    }
  }
  return true;
}

Method 2

function validate(theForm) {
  var elements = theForm.elements;
  for (var i = 1; i < elements.length ; i++) ( // no need to know how many
    if (elements[i].name.indexOf("Input_row")!=-1 && elements[i].value == "" ) {
      alert("Please fill in "+elements[i].name);
      return false;
    }
  }
  return true; // allow submit
}

using <form onsubmit="return valdiate(this)"..

Without inline code:

window.onload=function() {
  document.getElementById("formID").onsubmit=function() {
    var elements = this.elements;
    for (var i = 1; i < elements.length ; i++) ( // no need to know how many
      if (elements[i].name.indexOf("Input_row")!=-1 && elements[i].value == "" ) {
        alert("Please fill in "+elements[i].name);
        return false;
      }
    }
    return true; // allow submit
  }
}

What is the JavaScript code for validating a form, getting elements by name, with a loop?

1 Answers1