Question

Been trying to see how flexible this is. http://jsfiddle.net/PJSha/4/ i have changed the get element from Name to ClassName which both worked but does not work when i try and achieve it with Id… is there a reason

Code:

<link rel="stylesheet" href="http://code.jquery.com/ui/1.8.21/themes/base/jquery-ui.css" type="text/css" media="all" />

<input type="text" id="foo" class="bar" name="domain">
<div onclick="check_domain_input()">Click</div>

<div id="dialog" title="Attention!" style="display:none">
    Please enter a domain name to search for.
</div>

<script>
    function check_domain_input()  {        
        var domain_val = document.getElementById('foo');

        if (domain_val[0].value.length > 0) {
            return true;
        }

        $( "#dialog" ).dialog();

        return false;
    }
</script>

Answer 1

getElementsById should be getElementById (no s after Element). It only ever returns a reference to one element, or null.

Because it returns a reference, not a NodeList, the [0] is not necessary when you access its value property.