https://onesumxnils.com/Scripts/WebForms/Focus.js

1//CdnPath=http://ajax.aspnetcdn.com/ajax/4.5.1/1/WebForms.js
2function WebForm_FindFirstFocusableChild(control) {
3    if (!control || !(control.tagName)) {
4        return null;
5    }
6    var tagName = control.tagName.toLowerCase();
7    if (tagName == "undefined") {
8        return null;
9    }
10    var children = control.childNodes;
11    if (children) {
12        for (var i = 0; i < children.length; i++) {
13            try {
14                if (WebForm_CanFocus(children[i])) {
15                    return children[i];
16                }
17                else {
18                    var focused = WebForm_FindFirstFocusableChild(children[i]);
19                    if (WebForm_CanFocus(focused)) {
20                        return focused;
21                    }
22                }
23            } catch (e) {
24            }
25        }
26    }
27    return null;
28}
29function WebForm_AutoFocus(focusId) {
30    var targetControl;
31    if (__nonMSDOMBrowser) {
32        targetControl = document.getElementById(focusId);
33    }
34    else {
35        targetControl = document.all[focusId];
36    }
37    var focused = targetControl;
38    if (targetControl && (!WebForm_CanFocus(targetControl)) ) {
39        focused = WebForm_FindFirstFocusableChild(targetControl);
40    }
41    if (focused) {
42        try {
43            focused.focus();
44            if (__nonMSDOMBrowser) {
45                focused.scrollIntoView(false);
46            }
47            if (window.__smartNav) {
48                window.__smartNav.ae = focused.id;
49            }
50        }
51        catch (e) {
52        }
53    }
54}
55function WebForm_CanFocus(element) {
56    if (!element || !(element.tagName)) return false;
57    var tagName = element.tagName.toLowerCase();
58    return (!(element.disabled) &&
59            (!(element.type) || element.type.toLowerCase() != "hidden") &&
60            WebForm_IsFocusableTag(tagName) &&
61            WebForm_IsInVisibleContainer(element)
62            );
63}
64function WebForm_IsFocusableTag(tagName) {
65    return (tagName == "input" ||
66            tagName == "textarea" ||
67            tagName == "select" ||
68            tagName == "button" ||
69            tagName == "a");
70}
71function WebForm_IsInVisibleContainer(ctrl) {
72    var current = ctrl;
73    while((typeof(current) != "undefined") && (current != null)) {
74        if (current.disabled ||
75            ( typeof(current.style) != "undefined" &&
76            ( ( typeof(current.style.display) != "undefined" &&
77                current.style.display == "none") ||
78                ( typeof(current.style.visibility) != "undefined" &&
79                current.style.visibility == "hidden") ) ) ) {
80            return false;
81        }
82        if (typeof(current.parentNode) != "undefined" &&
83                current.parentNode != null &&
84                current.parentNode != current &&
85                current.parentNode.tagName.toLowerCase() != "body") {
86            current = current.parentNode;
87        }
88        else {
89            return true;
90        }
91    }
92    return true;
93}