如何编写If / else语句？

Question

x = 1;    
if(x = 10) {x = 1;} 
else {x = x + 1;}
alert (x);

The result is always 1 , instead of 1,2,3...

Answer 1

Replace

if(x = 10) {x = 1;} 

with

if(x == 10) {x = 1;} 

Because x=10 returns 10 , which in a test evaluates as true, and thus the code {x = 1;} is executed.

From the MDN about if...else :

Any value that is not undefined, null, 0, NaN, or the empty string (""), and any object, including a Boolean object whose value is false, evaluates to true when passed to a conditional statement

Answer 2

x = 1;    
if(x 

==

10) {x = 1;} 
    else {x = x + 1;}
    alert (x);

Answer 3

if condition should be checked like below

x=1;
if(x == 10)
{x = 1;}
else
{x = x+ 1;}
 alert(x)

Thanks

Answer 4

var x = 1;
x = (x == 10)? 1:x+=1;
alert(x);