javascript-multiple-input-textbox-validation

Question

I have n number of textboxes on a form. After the user enters a value in a textbox, I need to check that it's not a duplicate of any of the other textboxes. For example:

Textbox[0] : 1
Textbox[1] : 2 
Textbox[2] : 3
Textbox[4] : 1

It should alert saying that '1' has been entered twice.

I tried the following:

function findDuplicates ( obj ) {
    var inputs = document.getElementsByName('analog_idorder[]');
    var answers= new Array();

    for(var ii = 0; ii < inputs.length; ii++) {
        if(inputs[ii].type == 'text') {
            for(var jj = 0; jj < answers.length; jj++) {
                if(answers[jj] == inputs[ii].value)
                    alert('Duplicate Id_order number');
                return false;
            }
            answers.push(inputs[ii].value);
        }
    }
    return true;
}

But only the first two textboxes validate.

Let me know how I can solve this problem.

Have you made sure that the name, analog_idorder[], is actually the same for all textboxes? Try alert(inputs.length); on line 2, to see how many textboxes it found. Also, if you've, say, spelled 'text' wrong, as the type parameter, they would still show up as textboxes, but wouldn't meet your first criteria. try alert(ii) after the first 'if' as well. — David Hedlund
– David Hedlund, Commented Jul 14, 2009 at 6:39

Baversjo · Accepted Answer · 2009-07-14 06:38:02Z

1

Try adding brackets for the if statement in the nestled loop:

            for(var jj = 0; jj < answers.length; jj++){
                if(answers[jj] == inputs[ii].value){
                   alert('Duplicate Id_order number');
                   return false;
                }

            }

Else the loop will always return false at the first iteration.

answered Jul 14, 2009 at 6:38

Baversjo

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1 Comment

Murugesh Over a year ago

Thanks Baversjo i Will try out and let you know

seth · Accepted Answer · 2009-07-14 06:47:58Z

1

You could get rid of all the looping you are doing by using a associative array to store the values you've seen:

var answers = document.getElementsByName("analog_iorder[]");
var seen = {};

function checkForDupes() {
  for (var i=0;i<answers.length;i++) { 
    if (seen[ answers[i].value ]) { 
      alert("Duplicate "); 
      return false;
    } 
    seen[ answers[i].value ] = true; 
  }
  return true;
}

answered Jul 14, 2009 at 6:47

seth

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Comments

amantur · Accepted Answer · 2009-07-14 06:53:46Z

Text 1: <input type="text" id="txt1" onblur="chkValue('txt1');" /><br/>
Text 2: <input type="text" id="txt2" onblur="chkValue('txt2');" /><br/>
Text 3: <input type="text" id="txt3" onblur="chkValue('txt3');" /><br/>
Text 4: <input type="text" id="txt4" onblur="chkValue('txt4');" /><br/>
Text 5: <input type="text" id="txt5" onblur="chkValue('txt5');" /><br/>
Text 6: <input type="text" id="txt6" onblur="chkValue('txt6');" /><br/>
Text 7: <input type="text" id="txt7" onblur="chkValue('txt7');" /><br/>
Text 8: <input type="text" id="txt8" onblur="chkValue('txt8');" /><br/>
Text 9: <input type="text" id="txt9" onblur="chkValue('txt9');" /><br/>
Text 10: <input type="text" id="txt10" onblur="chkValue('txt10');" /><br/>

<script type="text/javascript">
var vals=new Object();

function chkValue(a)
{
    var t=document.getElementById(a);

    if(vals[t.value])
    {
        if(vals[t.value] != a)
        {
            alert("You have already entered ["+t.value+"]");
            t.value="";
        }
    }
    else
    {
        vals[t.value] = a;
    }
}

</script>

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