# @require-modules
The @require-modules directive is used to determine if a module exists, and if it does not, the component marked with this directive won't be resolved.
# Code example
When you run the following example, you won't see any buttons because the file-Propertyaddon isn't loaded.
<html>
<template id="layout-template">
<webpdf>
<group-list>
<!-- 'fpmodule' is a module defined in the 'file-property' addon which is not declared in the `addons:[]`, this group component will not be rendered -->
<group name="file-property" @require-modules="fpmodule">
<fpmodule:file-property-button></fpmodule:file-property-button>
</group>
</group-list>
<div class="fv__ui-body">
<viewer></viewer>
</div>
<template>
<fpmodule:file-property-dialog></fpmodule:file-property-dialog>
</template>
</webpdf>
</template>
</html>
<script>
var CustomAppearance = UIExtension.appearances.Appearance.extend({
getLayoutTemplate: function() {
return document.getElementById('layout-template').innerHTML;
}
});
var libPath = window.top.location.origin + '/lib';
var pdfui = new UIExtension.PDFUI({
viewerOptions: {
libPath: libPath,
jr: {
licenseSN: licenseSN,
licenseKey: licenseKey
}
},
renderTo: document.body,
appearance: CustomAppearance,
addons: [] // No addon is loaded
});
var origin = window.top.location.origin;
var url = origin + window.top.location.href.slice(origin.length).replace(/((\/.*)?\/docs\/).*/, '$1FoxitPDFSDKforWeb_DemoGuide.pdf');
pdfui.openPDFByHttpRangeRequest({
range: {
url: url,
}
}, { fileName: 'FoxitPDFSDKforWeb_DemoGuide.pdf' })
window.addEventListener(UIExtension.PDFViewCtrl.DeviceInfo.isDesktop ? 'resize' : 'orientationchange', function(e) {
pdfui.redraw().catch(function(err) {console.log(err)});
});
</script>
{
"iframeOptions": {
"style": "height: 500px"
}
}
When you run the following example, you will see the File Property because the file-Propertyaddon is loaded.
<html>
<template id="layout-template">
<webpdf>
<group-list>
<group name="file-property" @require-modules="fpmodule">
<fpmodule:file-property-button></fpmodule:file-property-button>
</group>
</group-list>
<div class="fv__ui-body">
<viewer></viewer>
</div>
<template>
<fpmodule:file-property-dialog></fpmodule:file-property-dialog>
</template>
</webpdf>
</template>
</html>
<script>
var CustomAppearance = UIExtension.appearances.Appearance.extend({
getLayoutTemplate: function() {
return document.getElementById('layout-template').innerHTML;
}
});
var libPath = window.top.location.origin + '/lib';
var pdfui = new UIExtension.PDFUI({
viewerOptions: {
libPath: libPath,
jr: {
licenseSN: licenseSN,
licenseKey: licenseKey
}
},
renderTo: document.body,
appearance: CustomAppearance,
addons: [
libPath + '/uix-addons/file-property'
] // the `file-property` addon will be loaded
});
var origin = window.top.location.origin;
var url = origin + window.top.location.href.slice(origin.length).replace(/((\/.*)?\/docs\/).*/, '$1FoxitPDFSDKforWeb_DemoGuide.pdf');
pdfui.openPDFByHttpRangeRequest({
range: {
url: url,
}
}, { fileName: 'FoxitPDFSDKforWeb_DemoGuide.pdf' })
window.addEventListener(UIExtension.PDFViewCtrl.DeviceInfo.isDesktop ? 'resize' : 'orientationchange', function(e) {
pdfui.redraw().catch(function(err) {console.log(err)});
});
</script>
{
"iframeOptions": {
"style": "height: 500px"
}
}