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JavaScript DataView.getFloat64()用法及代碼示例

JavaScript DataView.getFloat64() 是 dataView 中的一個內置方法。它用於在指定位置獲取有符號的 64 位浮點(double)數。

注意:64 位浮點數的範圍是從 -1.7+308 到 +1.7E+308。

用法

dataview.getFloat64(byteOffset)

參數

byteoffset: 從讀取數據的視圖開始的偏移量,以字節為單位。

返回值

一個有符號的 64 位浮點數。

瀏覽器支持

Chrome 9
Safari 5.1
Firefox 15
Opera 12.1

例子1

<script>
//JavaScript to illustrate dataview.getFloat64() method
// creating a ArrayBuffer 
var JavaTpoint = new ArrayBuffer(20);
// Creating a view
var arr = new DataView(JavaTpoint);
// 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>

輸出:

If we give a Float value then output will be
5.7

例子2

<script>
//JavaScript to illustrate dataview.getFloat64() method
// if there is no data to be stored then it returns Nan
// creating a ArrayBuffer 
var JavaTpoint = new ArrayBuffer(10);
// creating a view
var arr = new DataView(JavaTpoint);
// 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>

輸出:

if there is no data to be stored, then Output will Be:

NaN

例子3

<script>
//JavaScript to illustrate dataview.getFloat64() method
// creating a ArrayBuffer
var JavaTpoint = new ArrayBuffer(10);
// creating a view
var arr = new DataView(JavaTpoint);
//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>

輸出:

PI value will be
3.141592653589793




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注:本文由純淨天空篩選整理自 JavaScript DataView.getFloat64() method。非經特殊聲明,原始代碼版權歸原作者所有,本譯文未經允許或授權,請勿轉載或複製。