"apex:pageblocksection" must be terminated by the matching end-tag?

Question

I am trying to validate uid and pwd using a Visualforce page with javascript, but I'm getting an error saying the element type <apex:pageblocksection> must be terminated by the matching end-tag. What's wrong with this code?

<apex:page>
<script>
    Function f1(Uid){
        Var u = document.getElementByid(Uid).value;
                if(u == ''){
                        alert('Please Enter User name..')
                        document.getElementbyid(uid).focus()
                    }
        }
<script>
<apex:form>        
<apex:pageblock>

<apex:pageblocksection title="Entry section..">
    <apex:outputText Value = "Enter Uid.."></apex:outputText>
    <apex:inputText id="uid"/>
        <apex:commandbutton value="Submit" onclick="f1('{!$Component.uid}')"/>
<apex:pageblocksection>
    </apex:pageblock>
</apex:from>
</apex:page>

Answer 1

You're missing a forward slash on you closing tag, it should be:

  </apex:pageblocksection>
</apex:pageblock>