// read values with a string, same result as above // but works with special characters and spaces // and of course variables obj["key1"] === 1; obj["key2"] === 2; // read with a variable var key1Str = "key1"; obj[key1Str] === 1;
JS variable inside a string You can include a variable value inside a string using string interpolation or concatenation. var my_name = 'John'; var s = `hello ${my_name}, how are you doing`; console.log(s); // prints hello John, how are you doing Comment if you have any doubts ...
1)、ECMAScript是一个标准(欧洲计算机制造商协会),JavaScript只是它的一个实现,其他实现包括ActionScript(Flash脚本) 2)、ECMAScript可以为不同种类的宿主环境提供核心的脚本编程能力,即ECMAScript不与具体的宿主环境相绑定,如JavaScript的宿主环境是浏览器,AS的宿主环境是Flash。、 3)、ECMAScript描述了以下内容:语法、...
Backticks are generally used when you need to insert variables or expressions into a string. This is done by wrapping variables or expressions with ${variable or expression}. For example, // strings example let name1 = 'Peter'; let name2 = "Jack"; let result = `The names are ${name...
JavaScript Issue No. 9: Providing a String As the First Argument tosetTimeoutorsetInterval For starters, let’s be clear on something here: Providing a string as the first argument tosetTimeoutorsetIntervalisnotitself a mistake per se. It is perfectly legitimate JavaScript code. The issue he...
This means location.hash can be used in a manner similar to the variable name. However, there are a few notable differences. First is the fact that the value of location.hash is a string that always begins with #. In most browsers, this is a problem, which means that to execute ...
foo=4;// change variable `foo` 复制 复合赋值运算符 有复合赋值运算符,比如+=。以下两个赋值是等价的: x+=1;x=x+1; 复制 标识符和变量名 标识符是在 JavaScript 中扮演各种语法角色的名称。例如,变量的名称是标识符。标识符区分大小写。 大致而言,标识符的第一个字符可以是任何 Unicode 字母、美元符号...
If you put a number in quotes, it will be treated as a text string. Example constpi =3.14; letperson ="John Doe"; letanswer ='Yes I am!'; Try it Yourself » Declaring a JavaScript Variable Creating a variable in JavaScript is called "declaring" a variable. ...
//typeof操作符的操作数可以是变量(message)、也可以是数值字面量,操作符返回下列字符串"undefined":这个值未定义"boolean":布尔值"string":字符串"number":数值"object":对象或null"function":函数 eg:varmessage="some string"; alert(typeofmessage);//"string"alert(typeof(message));//"string"alert(typ...
Strings can be formed as follows: Literal string, formed by placing characters in double or single quotes. Variable whose value is a string primitive, formed by assigning a string literal, another string variable, or a string expression.