Alert ("two decimal places:" +a.fixed (2)+ "

Others:

? //Keep two decimal places

//Function: Rounds floating-point numbers to 2 decimal places?

Function? toDecimal(x)？ {?

var？ f？ =? parse float(x)； ?

What if? (Isnan (f))? {?

Return; ?

}?

f？ =? math . round(x * 100)/ 100； ?

Return? f； ?

}?

//The system reserves 2 decimal places, such as 2, which will be supplemented by 00. That's 2.00?

Function? toDecimal2(x)？ {?

var？ f？ =? parse float(x)； ?

What if? (Isnan (f))? {?

Return? Fake; ?

}?

var？ f？ =? math . round(x * 100)/ 100； ?

var？ s？ =? f . tostring()； ?

var？ rs？ =? s.indexOf(' . ')); ?

What if? (rs？ & lt？ 0)? {?

rs？ =? S. length; ?

s？ +=? '.'； ?

}?

What time? (s.length？ & lt=? rs？ +? 2)? {?

s？ +=? '0'; ?

}?

Return? s； ?

}?

Function? fomatFloat(src，pos){？

Return? math . round(src * math . pow( 10，？ pos))/Math.pow( 10，？ pos)； ?

}?

//circle?

Alert ("Keep 2 decimal places:"? +? toDecimal(3. 14 159267))； ?

Alert ("Forced to keep 2 decimal places:"? +? todecimal 2(3. 14 159267))； ?

Alert ("Keep 2 decimal places:"? +? toDecimal(3. 14559267))； ?

Alert ("Forced to keep 2 decimal places:"? +? todecimal 2(3. 15 159267))； ?

Alert ("Keep 2 decimal places:"? +? fomatFloat(3. 14559267，？ 2)); ?

Alert ("Reserved 1 Decimal:"? +? fomatFloat(3. 15 159267，？ 1)); ?

//A family of six?

Alert ("Keep 2 decimal places:"? +? 1000.003 . tofixed(2))； ?

Alert ("Reserved 1 Decimal:"? +? 1000.08 . tofixed( 1))； ?

Alert ("Reserved 1 Decimal:"? +? 1000.04 . tofixed( 1))； ?

Alert ("Reserved 1 Decimal:"? +? 1000.05 . tofixed( 1))； ?

//Scientific counting?

alert(3. 14 15 . toexponential(2))； ?

alert(3. 1455 . to exponential(2))； ?

alert(3. 1445 . to exponential(2))； ?

alert(3. 1465 . to exponential(2))； ?

alert(3. 1665 . to exponential( 1))； ?

//accurate to n bits, excluding n bits?

Alert ("accurate to the second decimal place"? +? 3. 14 15 . toprecision(2))； ?

Alert ("accurate to the third decimal place"? +? 3. 1465 . top precision(3))； ?

Alert ("accurate to the second decimal place"? +? 3. 14 15 . toprecision(2))； ?

Alert ("accurate to the second decimal place"? +? 3. 1455 . top precision(2))； ?

Alert ("accurate to the fifth decimal place"? +? 3. 14 1592679287 . to precision(5))；