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Keeping Templates Up-to-Date


In order to know which part of your HTML to update when an underlying property changes, Handlebars will insert marker elements with a unique ID. If you look at your application while it's running, you might notice these extra elements:

My new car is
<script id="metamorph-0-start" type="text/x-placeholder"></script>
blue
<script id="metamorph-0-end" type="text/x-placeholder"></script>.

Because all Handlebars expressions are wrapped in these markers, make sure each HTML tag stays inside the same block. For example, you shouldn't do this:

{{! Don't do it! }}
<div {{#if isUrgent}}class="urgent"{{/if}}>

If you want to avoid your property output getting wrapped in these markers, use the unbound helper:

My new car is {{unbound color}}.

Your output will be free of markers, but be careful, because the output won't be automatically updated!

My new car is blue.