<div id="help">
тут текст
</div>
<div id="number">
<span>Вес:</span><span id="fakespan" class="weight">100</span>
</div>
<script type='text/javascript'>
if (100 == 0 | document.getElementById('fakespan').textContent.trim()
document.getElementById('help').style = {display: 'none'};
</script>