How to get the numeric type of a variable in javascript? Or string type?

In JavaScript, you can use the typeof operator to get whether the variable is of numeric type or string type, the syntax is "typeof variable"; if the return value is "number", then the variable is of numeric type, if the return value is "string", the variable is of string type.

The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.

#Javascript determines whether a variable is a numeric type? Or string type?

In JavaScript, you can use the typeof operator to determine whether a variable is of numeric type or string type.

The typeof operator is used to detect the data type of a given variable or value. The returned value is the data type name of the operand, which is a string result.

The usage format is as follows:

typeof 操作数

Note: The operand can be a variable or a specific value (i.e. a literal). The return values ​​are as follows:

• undefined: indicates that the operand is undefined;

• boolean: indicates that the operand is a Boolean value;

• string: Indicates that the operand is a string;

• number: Indicates that the operand is a number;

• object: Indicates that the operand is an object or array ;

• function: Indicates that the operand is a function.

Note: Functions are also objects, but typeof treats functions as special cases, so when detecting functions, the returned result is function, not object.

An example of using the typeof operator to detect data types is as follows:

var miaov = 'ketang'; //声明变量，同时给变量赋值
console.log( typeof miaov );  //检测变量miaov，结果为：string
console.log( typeof 1 );  //检测数字1，结果为：number
console.log( typeof true );   //检测true，结果为：boolean
console.log( typeof false );  //检测false，结果为：boolean
console.log( typeof undefined );  //检测undefined，结果为：undefined
console.log( typeof null );  //检测null，结果为：object
console.log( typeof {} );  // 检测对象，结果为：object
console.log( typeof [] );  //检测数组，结果为：object
function func(){} //定义函数
console.log( typeof func );  //检测func函数类型，结果为：'function'

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