I am trying to write a portion of my webpage so that when the user enters in a year into a textbox, next to it, the test changes to show the next year. Ultimately it should liike like a year range, specifically for a school year (ie: 2000 - 2001, 2008 - 2009). Additionally, I would like to be able to have the "dynamic year" say "[Invalid]" if the user had not typed in a complete year yet.. (ie: 200 - [Invalid]). Once the user types in 4 digits, then the year range should display properly.
<span id="ctl00_MainContent_lblSchoolYear" style="display:inline-block;width:88px;">School-Year Start:</span>
<input name="ctl00$MainContent$txtSchoolYear" type="text" value="0000" maxlength="4" id="ctl00_MainContent_txtSchoolYear" style="width:32px;" />
<span id="ctl00_MainContent_lblSchoolYearRange"> - [EndYear]</span>