[译]javascript中的条件语句

本文翻译youtube上的up主kudvenkat的javascript tutorial播放单

源地址在此:

https://www.youtube.com/watch?v=PMsVM7rjupU&list=PL6n9fhu94yhUA99nOsJkKXBqokT3MBK0b

Javascript的代码是从上到下一条条运行的.如果出于某些原因你想要打乱这个顺序,或者当某些条件满足的时候优先处理某些语句的话.这时候我们就要用到条件语句了

Javascript有如下的条件语句

if

if else

if else if else

switch

ternary operator - 是if..else语句的一种简写

if的例子

var userInput = Number(prompt("Please enter a number", ""));
if (userInput == 1) 
{
    alert("You number is One");
}
if (userInput == 2) 
{
    alert("You number is Two");
}
if (userInput == 3) 
{
    alert("Your number is Three");
}
if(userInput != 1 && userInput != 2 && userInput != 3)
{
    alert("Your number is not between 1 and 3");
}

if-else if例子

var userInput = Number(prompt("Please enter a number", ""));
if (userInput == 1) 
{
    alert("You number is One");
}
else if (userInput == 2) 
{
    alert("You number is Two");
}
else if (userInput == 3) 
{
    alert("Your number is Three");
}
else 
{
    alert("Your number is not between 1 and 3");
}