Commonmark migration

#Javascript, 73 bytes

# Javascript, 73 bytes

Good ol' ES5 loops

for(a=c=0,b=(l=(s=prompt()).length)-1;a<~-l/2;c-=s[a++]-s[b--]);alert(!c)

What's happening here?

for(
a=c=0,               // a = left digits of the number
// c = the result
b=                   // b = right digits of number
(l=              // l = length of number - 1
(s=prompt()) // s = the number as input from user
.length)-1;

a<~-l/2;             // while a < length of number / 2, rounded down (~-)

c-=
s[a++]           // c -= left digit
-
s[b--]           // c += right digit (because - and - == +)
);
// for balanced numbers c should be 0
alert(!c)               // 0 equals false in javascript, so output the opposite of c


#Javascript, 73 bytes

Good ol' ES5 loops

for(a=c=0,b=(l=(s=prompt()).length)-1;a<~-l/2;c-=s[a++]-s[b--]);alert(!c)

What's happening here?

for(
a=c=0,               // a = left digits of the number
// c = the result
b=                   // b = right digits of number
(l=              // l = length of number - 1
(s=prompt()) // s = the number as input from user
.length)-1;

a<~-l/2;             // while a < length of number / 2, rounded down (~-)

c-=
s[a++]           // c -= left digit
-
s[b--]           // c += right digit (because - and - == +)
);
// for balanced numbers c should be 0
alert(!c)               // 0 equals false in javascript, so output the opposite of c


#Javascript, 73 bytes

Good ol' ES5 loops

for(a=c=0,b=(l=(s=prompt()).length)-1;a<~-l/2;c-=s[a++]-s[b--]);alert(!c)