Ich hatte gehofft, dass man aus dem kürzeren Quellcode schon das Problem erkennen könnte. Hier der HTML-Code eines nicht funktionierenden Beispiels, den ich allerdings kürzen musste, da er sonst hier nicht akzeptiert wurde.
<body>
<div id="logo">
<img src="/images/header.png">
</div>
<div id="downloadbutton">
<label class="button" onClick="DownloadSelected();">Download starten</label><span id="anzahl">0 Dateien gewählt</span>
</div>
<div id="download-area">
<input id="id" type="hidden" value="c84b22f1-3e4d-4918-acb6-29ab066b0917" />
<div id="header">
<input class="checkbox" id="selectall" type="image" src="images/unselected.png" onClick="selectall(this);" />
Alle Dateien oder Verzeichnisse
</div>
<div id="content">
<input class="checkbox left" type="image" src="/images/unselected.png" id="Pictos" onClick="selectdir(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos" data-type="dir" />
<details class="left" id="/var/www/html/upload/20220930T114032410Z/Pictos"><summary>Pictos</summary>
<input class="checkbox left" type="image" src="/images/unselected.png" id="Design" onClick="selectdir(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Design" data-type="dir" />
<details class="left" id="/var/www/html/upload/20220930T114032410Z/Pictos/Design"><summary>Design</summary>
<input class="checkbox" type="image" src="/images/unselected.png" id="Interior Light.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Design/Interior Light.pdf" data-type="file" data-size="281496" />Interior Light.pdf (274.9 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="LED Light Show.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Design/LED Light Show.pdf" data-type="file" data-size="296662" />LED Light Show.pdf (289.71 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Mood Light.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Design/Mood Light.pdf" data-type="file" data-size="263734" />Mood Light.pdf (257.55 KB)<br/>
</details>
<input class="checkbox left" type="image" src="/images/unselected.png" id="Handling" onClick="selectdir(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Handling" data-type="dir" />
<details class="left" id="/var/www/html/upload/20220930T114032410Z/Pictos/Handling"><summary>Handling</summary>
<input class="checkbox" type="image" src="/images/unselected.png" id="Control Center.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Handling/Control Center.pdf" data-type="file" data-size="285338" />Control Center.pdf (278.65 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Eco Tech.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Handling/Eco Tech.pdf" data-type="file" data-size="287530" />Eco Tech.pdf (280.79 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="NFC Connect.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Handling/NFC Connect.pdf" data-type="file" data-size="297870" />NFC Connect.pdf (290.89 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Set-up Manager.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Handling/Set-up Manager.pdf" data-type="file" data-size="241894" />Set-up Manager.pdf (236.22 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Voice Guide.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Handling/Voice Guide.pdf" data-type="file" data-size="279085" />Voice Guide.pdf (272.54 KB)<br/>
</details>
<input class="checkbox left" type="image" src="/images/unselected.png" id="Komfort" onClick="selectdir(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort" data-type="dir" />
<details class="left" id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort"><summary>Komfort</summary>
<input class="checkbox" type="image" src="/images/unselected.png" id="Body Acrylic.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Body Acrylic.pdf" data-type="file" data-size="277946" />Body Acrylic.pdf (271.43 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Body Curve.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Body Curve.pdf" data-type="file" data-size="276776" />Body Curve.pdf (270.29 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Body Seat.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Body Seat.pdf" data-type="file" data-size="279966" />Body Seat.pdf (273.4 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Body Shape.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Body Shape.pdf" data-type="file" data-size="284472" />Body Shape.pdf (277.8 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Body Shape_208x80.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Body Shape_208x80.pdf" data-type="file" data-size="285627" />Body Shape_208x80.pdf (278.93 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Body Shape_208x90.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Body Shape_208x90.pdf" data-type="file" data-size="285610" />Body Shape_208x90.pdf (278.92 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Body Space_70x70x205.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Body Space_70x70x205.pdf" data-type="file" data-size="282066" />Body Space_70x70x205.pdf (275.46 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Body Space_86x208.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Body Space_86x208.pdf" data-type="file" data-size="287240" />Body Space_86x208.pdf (280.51 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Bodyform Plus.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Bodyform Plus.pdf" data-type="file" data-size="287548" />Bodyform Plus.pdf (280.81 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Comfort Cooling PLUS.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Comfort Cooling PLUS.pdf" data-type="file" data-size="839018" />Comfort Cooling PLUS.pdf (819.35 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Comfort Cooling.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Comfort Cooling.pdf" data-type="file" data-size="282031" />Comfort Cooling.pdf (275.42 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Frosted Acrylic.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Frosted Acrylic.pdf" data-type="file" data-size="280600" />Frosted Acrylic.pdf (274.02 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="MP3 AUX.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/MP3 AUX.pdf" data-type="file" data-size="282353" />MP3 AUX.pdf (275.74 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Single Sound.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Single Sound.pdf" data-type="file" data-size="289764" />Single Sound.pdf (282.97 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Top Cooling.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Top Cooling.pdf" data-type="file" data-size="281260" />Top Cooling.pdf (274.67 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Vibra Shape.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Komfort/Vibra Shape.pdf" data-type="file" data-size="304822" />Vibra Shape.pdf (297.68 KB)<br/>
</details>
<input class="checkbox" type="image" src="/images/unselected.png" id="Pictoübersicht.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Pictoübersicht.pdf" data-type="file" data-size="341613" />Pictoübersicht.pdf (333.61 KB)<br/>
<input class="checkbox left" type="image" src="/images/unselected.png" id="Power" onClick="selectdir(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Power" data-type="dir" />
<details class="left" id="/var/www/html/upload/20220930T114032410Z/Pictos/Power"><summary>Power</summary>
<input class="checkbox" type="image" src="/images/unselected.png" id="Advanced Performance.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Power/Advanced Performance.pdf" data-type="file" data-size="838174" />Advanced Performance.pdf (818.53 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Back Tan.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Power/Back Tan.pdf" data-type="file" data-size="283166" />Back Tan.pdf (276.53 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Shoulder Tan_2x240W.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Power/Shoulder Tan_2x240W.pdf" data-type="file" data-size="275742" />Shoulder Tan_2x240W.pdf (269.28 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Smart Performance.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Power/Smart Performance.pdf" data-type="file" data-size="833570" />Smart Performance.pdf (814.03 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Smart Power.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Power/Smart Power.pdf" data-type="file" data-size="278059" />Smart Power.pdf (271.54 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Sun Select.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Power/Sun Select.pdf" data-type="file" data-size="305166" />Sun Select.pdf (298.01 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Ultra Performance+.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Power/Ultra Performance+.pdf" data-type="file" data-size="558586" />Ultra Performance+.pdf (545.49 KB)<br/>
<input class="checkbox" type="image" src="/images/unselected.png" id="Ultra Power Plus.pdf" onClick="selectfile(this);" value=" " data-id="/var/www/html/upload/20220930T114032410Z/Pictos/Power/Ultra Power Plus.pdf" data-type="file" data-size="279169" />Ultra Power Plus.pdf (272.63 KB)<br/>
</details>
</details>
</div>
</div>
</body>
LG Peters