1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
| /* jshint browser: true */
(function () {
// We'll copy the properties below into the mirror div.
// Note that some browsers, such as Firefox, do not concatenate properties
// into their shorthand (e.g. padding-top, padding-bottom etc. -> padding),
// so we have to list every single property explicitly.
var properties = [
'direction', // RTL support
'boxSizing',
'width', // on Chrome and IE, exclude the scrollbar, so the mirror div wraps exactly as the textarea does
'height',
'overflowX',
'overflowY', // copy the scrollbar for IE
'borderTopWidth',
'borderRightWidth',
'borderBottomWidth',
'borderLeftWidth',
'borderStyle',
'paddingTop',
'paddingRight',
'paddingBottom',
'paddingLeft',
// https://developer.mozilla.org/en-US/docs/Web/CSS/font
'fontStyle',
'fontVariant',
'fontWeight',
'fontStretch',
'fontSize',
'fontSizeAdjust',
'lineHeight',
'fontFamily',
'textAlign',
'textTransform',
'textIndent',
'textDecoration', // might not make a difference, but better be safe
'letterSpacing',
'wordSpacing',
'tabSize',
'MozTabSize'
];
var isBrowser = (typeof window !== 'undefined');
var isFirefox = (isBrowser && window.mozInnerScreenX != null);
function getCaretCoordinates(element, position, options) {
if (!isBrowser) {
throw new Error('textarea-caret-position#getCaretCoordinates should only be called in a browser');
}
var debug = options && options.debug || false;
if (debug) {
var el = document.querySelector('#input-textarea-caret-position-mirror-div');
if (el) el.parentNode.removeChild(el);
}
// The mirror div will replicate the textarea's style
var div = document.createElement('div');
div.id = 'input-textarea-caret-position-mirror-div';
document.body.appendChild(div);
var style = div.style;
var computed = window.getComputedStyle ? window.getComputedStyle(element) : element.currentStyle; // currentStyle for IE < 9
var isInput = element.nodeName === 'INPUT';
// Default textarea styles
style.whiteSpace = 'pre-wrap';
if (!isInput)
style.wordWrap = 'break-word'; // only for textarea-s
// Position off-screen
style.position = 'absolute'; // required to return coordinates properly
if (!debug)
style.visibility = 'hidden'; // not 'display: none' because we want rendering
// Transfer the element's properties to the div
properties.forEach(function (prop) {
if (isInput && prop === 'lineHeight') {
// Special case for <input>s because text is rendered centered and line height may be != height
if (computed.boxSizing === "border-box") {
var height = parseInt(computed.height);
var outerHeight =
parseInt(computed.paddingTop) +
parseInt(computed.paddingBottom) +
parseInt(computed.borderTopWidth) +
parseInt(computed.borderBottomWidth);
var targetHeight = outerHeight + parseInt(computed.lineHeight);
if (height > targetHeight) {
style.lineHeight = height - outerHeight + "px";
} else if (height === targetHeight) {
style.lineHeight = computed.lineHeight;
} else {
style.lineHeight = 0;
}
} else {
style.lineHeight = computed.height;
}
} else {
style[prop] = computed[prop];
}
});
if (isFirefox) {
// Firefox lies about the overflow property for textareas: https://bugzilla.mozilla.org/show_bug.cgi?id=984275
if (element.scrollHeight > parseInt(computed.height))
style.overflowY = 'scroll';
} else {
style.overflow = 'hidden'; // for Chrome to not render a scrollbar; IE keeps overflowY = 'scroll'
}
div.textContent = element.value.substring(0, position);
// The second special handling for input type="text" vs textarea:
// spaces need to be replaced with non-breaking spaces - http://stackoverflow.com/a/13402035/1269037
if (isInput)
div.textContent = div.textContent.replace(/\s/g, '\u00a0');
var span = document.createElement('span');
// Wrapping must be replicated *exactly*, including when a long word gets
// onto the next line, with whitespace at the end of the line before (#7).
// The *only* reliable way to do that is to copy the *entire* rest of the
// textarea's content into the <span> created at the caret position.
// For inputs, just '.' would be enough, but no need to bother.
span.textContent = element.value.substring(position) || '.'; // || because a completely empty faux span doesn't render at all
div.appendChild(span);
var coordinates = {
top: span.offsetTop + parseInt(computed['borderTopWidth']),
left: span.offsetLeft + parseInt(computed['borderLeftWidth']),
height: parseInt(computed['lineHeight'])
};
if (debug) {
span.style.backgroundColor = '#aaa';
} else {
document.body.removeChild(div);
}
return coordinates;
}
if (typeof module != 'undefined' && typeof module.exports != 'undefined') {
module.exports = getCaretCoordinates;
} else if(isBrowser) {
window.getCaretCoordinates = getCaretCoordinates;
}
}());
|