Access RadComboBox value from Clientside javascript

Hi All,
I want to access RadComboBox, ie. whatever I type in the radcombobox from clientside javascript.
Posted below is my code where RadComboBox1 is the ID of my radcombobox. The problem with this code is  even if i enter a value in the radcombobox, it still fires the alert. Can anyone please help me?
 
var RadComboBox1 = document.all.RadComboBox1;   
   if (RadComboBox1.value.length == 0)
   {
    alert('Please enter an email address in the \'To\' field');
    RadComboBox1.focus();
    return false;
   }
   
 
thanks in anticipation!
mavericky
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