Simulate 'placeholder' with Javascript

clickClear.js

// clear the email address field when the user clicks into it
function clickClear(e) {
  if (e.value == 'Your email address') {  // text must match the default value attribute on the <input> tag
    e.value = '';
  }
}

input.html

<!-- here's the html snippet.  The important bits are the value and onfocus attributes -->

<input name="Email" id="Email" 
       type="text" value="Your email address"
       maxlength="255" tabindex="2"
       onfocus="clickClear(this);" />