isSafeInteger()Number对象的功能接受一个数字并确定它是否为安全整数。如果给定的数字是安全整数，则返回true，否则返回false。
其语法如下
Number.isSafeInteger(90071991);
<html>
<head>
<title>JavaScript Example</title>
</head>
<body>
<script type="text/javascript">
var result = Number.isSafeInteger(90071991);
if(result) {
document.write("Given number is a safe integer");
}else {
document.write("Given number is not a safe integer");
}
</script>
</body>
</html>输出结果
Given number is a safe integer
将十进制值，负值和一个方程式传递给此函数。
<html>
<head>
<title>JavaScript Example</title>
</head>
<body>
<script type="text/javascript">
var result1 = Number.isSafeInteger(45.2);
document.write(result1);
document.write("<br>");
var result2 = Number.isSafeInteger(-38);
document.write(result2);
document.write("<br>");
var result3 = Number.isSafeInteger(0/8);
document.write(result3);
document.write("<br>");
</script>
</body>
</html>输出结果
false true true