aspnetmvc-402314-common-features-client-side-functionality-how-to-register-javascript-on-devexpress-callbacks.md
If a script appears on a callback, browsers do not recognize it. DevExpress extensions implement a client-side mechanism that evaluates and executes scripts passed to a client in callbacks.
There are two types of scripts: external scripts and inline scripts.
An external script is loaded from an external file. This script is registered only once for the first callback. Add the dxis_ prefix to the id attribute value to register an external script.
<script id="dxis_myCode1" src="MyJavaScript.js" type="text/javascript"></script>
An inline script is embedded in HTML. This code is registered and executed on every callback. Add the dxss_ prefix to the id attribute value to register an inline script.
<script id="dxss_myCode2" type="text/javascript">
alert("This is custom script block");
</script>
View Example: How to register and execute a JavaScript downloaded to the client via a callback
If you load a script in the CallbackPanel container’s callback and then use the script outside the container, you should explicitly assign functions in your script to the global window object.
<script id="dxss_myCode3" type="text/javascript">
window.showText = function () {
alert('showText');
}
</script>
<input type="button" value="Show text" onclick="window.showText();"/>