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Question

javascript validation for empty input field

Answer 1

+4 A:

See the working example here

You are missing the required <form> element. Here is how your code should be like:

function IsEmpty(){
  if(document.forms['frm'].question.value == "")
  {
    alert("empty");
    return false;
  }
    return true;
}

HTML:

<form name="frm">
  Question: <input name="question"/> <br />
  <input id="insert" onclick="return IsEmpty();" type="submit" value="Add Question"/>
</form>

Sarfraz 2010-10-14 21:02:48

Answer 2

A:

Add an id "question" to your input element and then try this:

   if( document.getElementById('question').value === '' ){
      alert('empty');
    }

The reason your current code doesn't work is because you don't have a FORM tag in there. Also, lookup using "name" is not recommended as its deprecated.

See @Paul Dixon's answer in this post : http://stackoverflow.com/questions/608222/is-the-name-attribute-considered-outdated-for-a-anchor-tags

Rajat 2010-10-14 21:04:41

Answer 3

A:

if(document.getElementById("question").value == "")
{
    alert("empty")
}

Kenneth J 2010-10-14 21:04:49

... there's no "id" attribute on the `<input>` element; this would only work in IE because IE is broken.

Pointy 2010-10-14 21:05:43

sorry, I thought there was an ID, document.getElementsByName("question")[0].value, or just add an ID to the element

Kenneth J 2010-10-18 16:23:02

Answer 4

A:

Just add an ID tag to the input element... ie:

and check the value of the element in you javascript:

document.getElementById("question").value

Oh ya, get get firefox/firebug. It's the only way to do javascript.

Bal 2010-10-14 21:05:17

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javascript validation for empty input field

See the working example here

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