Checkbox Required

<script>
var checkobj

function agreesubmit(el){
checkobj=el
if (document.all||document.getElementById){
for (i=0;i<checkobj.form.length;i++){  //hunt down submit button
var tempobj=checkobj.form.elements[i]
if(tempobj.type.toLowerCase()=="submit")
tempobj.disabled=!checkobj.checked
}
}
}

function defaultagree(el){
if (!document.all&&!document.getElementById){
if (window.checkobj&&checkobj.checked)
return true
else{
alert("Please read/accept terms to submit form")
return false
}
}
}

</script>
  <p>&nbsp;</p>
  <p align="center">Before you continue, please read the terms and conditions below</p>
  <div align="center"></div>
  <form name="agreeform" action="youraction.html" onSubmit="return defaultagree(this)">
    <div align="center">
      <div align="center">
        <textarea name="textarea" id="textarea" cols="60" rows="4">This is where you would put your text</textarea>
      </div>
      <br>
      <input name="agreecheck" type="checkbox" onClick="agreesubmit(this)">
      <b>I agree to the above terms</b><br>
      <input type="Submit" value="Agree to these terms" disabled>
    </div>
  </form>

<script>
//change two names below to your form's names
document.forms.agreeform.agreecheck.checked=false
</script>