本文概述
一元运算符：一元运算仅包含一个操作数。在此, " +"一元加运算符将其操作数转换为Number类型。同时它还充当具有两个操作数的算术运算符, 在计算时返回加法结果。
JavaScript标识符：Javascript标识符用于命名变量(以及关键字, 函数和标签)。在Javascript中, 第一个字符必须是字母, 下划线(_)或美元符号($), 但不能为数字, 后续的字符可以是字母, 数字, 下划线或美元符号。
JavaScript + _运算子：它是带符号下划线(_)的变量和一元加号(+)运算符的组合, +运算符将_变量的类型转换为Number类型以进行进一步的操作。
例子：字符串类型的变量" _"存储在数字类型的变量" r"中。
- 输入如下：
var _ = "1"; var r = +_;
- 输出如下：
typeof(r) will be number
范例1：字符串到数字的转换
的HTML
<!DOCTYPE html>
< html >
< head >
< title >Javascript Operator</ title >
< script type = "text/javascript" ></ script >
< link rel = "stylesheet"
href = "https://www.lsbin.com/w3css/4/w3.css" />
</ head >
< body >
< div class = "conintainer" >
< p class = "w3-jumbo w3-text-green pad"
align = "center"
style = "margin: 0 0 0 0;" >
lsbin
</ p >
< p class = "w3-large w3-text-green pad"
align = "center" >
A computer science portal for geeks
</ p >
< p align = "center" >
Type of variable(_) :
< span id = "gfg" ></ span > < br />
Type of variable(a) :
< span id = "gfg1" ></ span >
</ p >
< script type = "text/javascript" >
GFG = function (_) {
let b = typeof _;
let a = +_;
let c = typeof a;
document.getElementById("gfg").innerHTML = b;
document.getElementById("gfg1").innerHTML = c;
};
GFG("21");
</ script >
</ div >
</ body >
</ html >输出如下：
范例2：通过将它们转换为数字类型来执行算术加法运算。
的HTML
<!DOCTYPE html>
< html >
< head >
< title >Addition Operation</ title >
< script type = "text/javascript" ></ script >
< link rel = "stylesheet"
href = "https://www.lsbin.com/w3css/4/w3.css" />
</ head >
< body >
< div class = "conintainer" >
< p class = "w3-jumbo w3-text-green pad"
align = "center"
style = "margin: 0 0 0 0;" >
lsbin
</ p >
< p class = "w3-large w3-text-green pad"
align = "center" >
A computer science portal for geeks
</ p >
< p align = "center" >
Value variable(_) :
< span id = "gfg" ></ span > < br />
Value of variable($) :
< span id = "gfg1" ></ span > < br />
Value of variable(Sum) :
< span id = "gfg2" ></ span >
</ p >
< script type = "text/javascript" >
GFG = function (_, $) {
let c = +_ + +$;
let a = +_;
let b = +$;
document.getElementById("gfg").innerHTML = a;
document.getElementById("gfg1").innerHTML = b;
document.getElementById("gfg2").innerHTML = c;
};
GFG("21", "45");
</ script >
</ div >
</ body >
</ html >输出如下：
