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
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
|
---
title: Math.floor()
slug: Web/JavaScript/Reference/Global_Objects/Math/floor
tags:
- JavaScript
- Math
- Method
translation_of: Web/JavaScript/Reference/Global_Objects/Math/floor
---
<div>{{JSRef("Global_Objects", "Math")}}</div>
<h2 id="Summary" name="Summary">Resumo</h2>
<p>A função <code><strong>Math.floor(x)</strong></code> retorna o menor número inteiro dentre o número "x".</p>
<h2 id="Syntax" name="Syntax">Sintaxe</h2>
<pre class="syntaxbox"><code>Math.floor(<em>x</em>) </code></pre>
<h3 id="Parameters" name="Parameters">Parâmetros</h3>
<dl>
<dt><code>x</code></dt>
<dd>Um número.</dd>
</dl>
<h2 id="Description" name="Description">Descrição</h2>
<p>Por <code>floor</code> ser um método estático de <code>Math</code>, você sempre irá usar como <code>Math.floor()</code>,e não como método do objeto <code>Math que você criou</code>.</p>
<h2 id="Examples" name="Examples">Exemplos</h2>
<h3 id="Example:_Using_Math.floor" name="Example:_Using_Math.floor">Exemplo: Usando <code>Math.floor</code></h3>
<pre class="brush:js">Math.floor( 45.95); // 45
Math.floor(-45.95); // -46
</pre>
<h3 id="Example:_Decimal_adjustment" name="Example:_Decimal_adjustment">Exemplo: Ajuste Decimal</h3>
<pre class="brush:js">// Closure
(function(){
/**
* Decimal adjustment of a number.
*
* @param {String} type The type of adjustment.
* @param {Number} value The number.
* @param {Integer} exp The exponent (the 10 logarithm of the adjustment base).
* @returns {Number} The adjusted value.
*/
function decimalAdjust(type, value, exp) {
// If the exp is undefined or zero...
if (typeof exp === 'undefined' || +exp === 0) {
return Math[type](value);
}
value = +value;
exp = +exp;
// If the value is not a number or the exp is not an integer...
if (isNaN(value) || !(typeof exp === 'number' && exp % 1 === 0)) {
return NaN;
}
// Shift
value = value.toString().split('e');
value = Math[type](+(value[0] + 'e' + (value[1] ? (+value[1] - exp) : -exp)));
// Shift back
value = value.toString().split('e');
return +(value[0] + 'e' + (value[1] ? (+value[1] + exp) : exp));
}
// Decimal round
if (!Math.round10) {
Math.round10 = function(value, exp) {
return decimalAdjust('round', value, exp);
};
}
// Decimal floor
if (!Math.floor10) {
Math.floor10 = function(value, exp) {
return decimalAdjust('floor', value, exp);
};
}
// Decimal ceil
if (!Math.ceil10) {
Math.ceil10 = function(value, exp) {
return decimalAdjust('ceil', value, exp);
};
}
})();
// Round
Math.round10(55.55, -1); // 55.6
Math.round10(55.549, -1); // 55.5
Math.round10(55, 1); // 60
Math.round10(54.9, 1); // 50
Math.round10(-55.55, -1); // -55.5
Math.round10(-55.551, -1); // -55.6
Math.round10(-55, 1); // -50
Math.round10(-55.1, 1); // -60
// Floor
Math.floor10(55.59, -1); // 55.5
Math.floor10(59, 1); // 50
Math.floor10(-55.51, -1); // -55.6
Math.floor10(-51, 1); // -60
// Ceil
Math.ceil10(55.51, -1); // 55.6
Math.ceil10(51, 1); // 60
Math.ceil10(-55.59, -1); // -55.5
Math.ceil10(-59, 1); // -50
</pre>
<h2 id="Especificações">Especificações</h2>
<table class="standard-table">
<tbody>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
<tr>
<td>ECMAScript 1st Edition. Implemented in JavaScript 1.0</td>
<td>Standard</td>
<td>Initial definition.</td>
</tr>
<tr>
<td>{{SpecName('ES5.1', '#sec-15.8.2.9', 'Math.floor')}}</td>
<td>{{Spec2('ES5.1')}}</td>
<td> </td>
</tr>
<tr>
<td>{{SpecName('ES6', '#sec-math.floor', 'Math.floor')}}</td>
<td>{{Spec2('ES6')}}</td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="Browser_compatibility">Compatibilidade com navegadores</h2>
<p>{{ CompatibilityTable() }}</p>
<div id="compat-desktop">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Chrome</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari</th>
</tr>
<tr>
<td>Basic support</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
</tr>
</tbody>
</table>
</div>
<div id="compat-mobile">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Chrome for Android</th>
<th>Firefox Mobile (Gecko)</th>
<th>IE Mobile</th>
<th>Opera Mobile</th>
<th>Safari Mobile</th>
</tr>
<tr>
<td>Basic support</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
</tr>
</tbody>
</table>
</div>
<h2 id="See_also" name="See_also">Veja também</h2>
<ul>
<li>The {{jsxref("Global_Objects/Math", "Math")}} object it belongs to.</li>
<li>{{jsxref("Math.abs")}}</li>
<li>{{jsxref("Math.ceil()")}}</li>
<li>{{jsxref("Math.round()")}}</li>
</ul>
|
