Javascript if/else语句
我的语法有错误。我不知道我错在哪里Javascript if/else语句,javascript,Javascript,我的语法有错误。我不知道我错在哪里 // Check if the user is ready to play! confirm("I am ready to play!"); var age = 13; var age = prompt("What's your age?"); if(var age === 13) { console.log("You are allowed to play but at your own risk."); } else { console.log
// Check if the user is ready to play!
confirm("I am ready to play!");
var age = 13;
var age = prompt("What's your age?");
if(var age === 13)
{
console.log("You are allowed to play but at your own risk.");
}
else
{
console.log(Play on!");
}
只需使用
var
声明变量一次:
// Check if the user is ready to play!
confirm("I am ready to play!");
var age = prompt("What's your age?");
if (age === '13') { // age will be a string
console.log("You are allowed to play but at your own risk.");
} else {
console.log("Play on!");
}
由于无法在if
语句中声明变量,因此会出现语法错误
另外,请注意,您在上一个控制台.log中缺少一个“
;这也会导致语法错误
您还存在一些逻辑问题。首先,age
将是一个字符串,而不是整数,因此age===13
将永远不会匹配。此外,将age
初始化为13
并立即重新分配它是没有意义的。您不能在if中声明变量statement@DaveAnderson这只是编解码器的一部分关于学习使用if/else语句的y课程。此外,“age”将是一个字符串,显式“==”将永远不匹配。
//this is another solution
confirm("I am ready to play!");
var age = prompt("What's your age?");//input type will be string
age = parseInt(age); //can convert to number by parseInt
if( age === 13)
{
alert("You are allowed to play but at your own risk.");
}
else
{
alert("Play on!");
}