DataView.getFloat64()
JavaScript
DataView.getFloat64()是dataView中的内置方法。用于在指定位置获取带符号的64位float(double)数字。
注意：注意：64位浮点数的范围是-1.7 + 308到+ 1.7E + 308。
语法
dataview.getFloat64(byteOffset)
参数
byteoffset ：从读取数据的视图开始处的偏移量(以字节为单位)。
返回值
一个带符号的64位浮点数。
浏览器支持
| Chrome |
9 |
| Safari |
5.1 |
| Firefox |
15 |
| Opera |
12.1 |
示例1
<script>
//JavaScript to illustrate dataview.getFloat64() method
// creating a ArrayBuffer
var lidihuo = new ArrayBuffer(20);
// Creating a view
var arr = new DataView(lidihuo);
// put the value 5.7 at slot 1
arr.setFloat64(1,5.7);
document.write("If we give a Float value then output will be<br><br>");
document.write(arr.getFloat64(1));
//expected output:5.7
</script>
输出：
如果我们给出一个Float值，那么输出将是
5.7
示例2
<script>
//JavaScript to illustrate dataview.getFloat64() method
// if there is no data to be stored then it returns Nan
// creating a ArrayBuffer
var lidihuo = new ArrayBuffer(10);
// creating a view
var arr = new DataView(lidihuo);
// NO Data
arr.setFloat64(1);
document.write(" if there is no data to be stored, then Output will Be:<br><br>")
document.write(arr.getFloat64(1));
//expected output:NAN
</script>
输出：
如果没有要存储的数据，则输出将为：
N
示例3
<script>
//JavaScript to illustrate dataview.getFloat64() method
// creating a ArrayBuffer
var lidihuo = new ArrayBuffer(10);
// creating a view
var arr = new DataView(lidihuo);
//We can also use math function like Math.PI
document.write("PI value will be<br><br>");
arr.setFloat64(1,Math.PI);
document.write(arr.getFloat64(1));
//expected output: 3.141592653589793
</script>
输出：
PI值将是
3.141592653589793
