Kichupo cha kifupi cha JavaScript

Ufafanuzi na matumizi

Kichupo cha kifupi kinafanya kufanya kazi kwa kipakuo kubwa.

Kichupo cha kifupi cha JavaScript kina kina kiwemoja cha 'kifupi' kwa kumwambika kwa ujumbe zaidi. Kwa kichupo cha kifupi hizi, kina hufanyia kufanya kazi kama kina cheti kati ya kipakuo kubwa. Hii inaonesha mafanikio kwa ifupi zaidi ya ifua kubwa ifuatili ifua.

Kwa hali inafikia hisia. Ikiwa kimekabalia, inafikia kwa hali kila hali inayofikia kwenye struktura. Ikiwa kimekabalia, inafanywa kwa kikodi kinachotumika.

Kwa hali inaweza kutumika na kichwa cha kwanza cha break au kichwa cha kwanza cha default (au zote mbili) au zikizofikia. Hii ni chaguo lake:

Kichwa cha kwanza cha break kinasaidia kutekeleza kwa kikodi cha kwanza cha kwa hali. Kwa kumaliza kufanya kikodi zaidi kwenye kikodi cha kwanza cha kwa hali na/au kufikia matokeo ya hali, kwa kuswa break. Ikiwa kuswa, kufanya kikodi kinachotumika kwa kikodi cha kwanza cha kwa hali kinaendelea.

Ikiwa hakuna hali yenye ufwicho, kichwa cha kwanza cha default kinachotumika kumfanya kwa kikodi kinachotumika. Kikodi cha kwanza cha kwa hali inaweza kuwa chaguo lake, la lako, lakini inaradhiswa kuwa inatumiwa kwa matukio yaliyofikia kwenye mashambulizi.

Mifano

Wendani kufanya kikodi kinachotumika kwa muhtasari wa kufikia:

var text;
var fruits = document.getElementById("myInput").value;
kwa hali(fruits) {
  kwa hali "Banana":
    text = "Banana ni kwa heri!";
    break;
  kwa hali "Orange":
    text = "Sikuangu na haitakuwa mwenye faniki wa juja.";
    break;
  kwa hali "Apple":
    text = "How you like them apples?";
    break;
  default:
    text = "Sikiuminijua kwa matunda hiyo...";
}

Jifunze tena

Hali zaidi zimeonyeshe katika ukurasa huo chini. TIY

Muundo

kwa hali(hisia) {
  kwa hali n:
    kikodi cha kichwa
    break;
  kwa hali n:
    kikodi cha kichwa
    break;
  default:
    kikodi cha kichwa cha kwanza
}

Makusanyiko ya hisia

Makusanyiko Kuchagulia
hisia Inahitajika. Kuchukua hisia la uendingaji. Hisia huitwa mara moja. Hisia huitwa kumueleza kwa jina la kichwa kila muda. Ikiwa kimekabalia, inafanywa kwa kikodi kinachotumika.

Vitoezi vya mawasiliano

Versio ya JavaScript： ECMAScript 1

Mafanikio zaidi

Mifano

Tumia namba wa weekday ya leo kumatua jina la weekday (Jumakuu=0, Jumapanda=1, Jumapili=2, ...)：

var siku;
switch (new Date().getDay()) {
  case 0:
    siku = "Jumakuu";
    break;
  case 1:
    siku = "Jumapanda";
    break;
  case 2:
    siku = "Jumapili";
    break;
  case 3:
    siku = "Jumatatu";
    break;
  case 4:
    siku = "Jumamosi";
    break;
  case 5:
    day = "Friday";
    break;
  case 6:
    day = "Saturday";
    break;
  default:
    day = "Unknown Day";
}

Jifunze tena

Mifano

If today is neither Saturday nor Sunday, write a default message:

var text;
switch (new Date().getDay()) {
  case 6:
    text = "Today is Saturday";
    break; 
  case 0:
    text = "Today is Sunday";
    break; 
  default: 
    text = "Looking forward to the Weekend";
}

Jifunze tena

Mifano

Sometimes you may want different cases to use the same code, or use the same default value.

Please note that in this example, cases share the same code block, and the default case does not have to be the last case in the switch block (but, if the default is not the last case in the switch block, remember to end it with a break).

var text;
switch (new Date().getDay()) {
  case 1:
  case 2:
  case 3:
  default: 
    text = "Looking forward to the Weekend";
    break; 
  case 4:
  case 5:
    text = "Soon it is Weekend";
    break; 
  case 0:
  case 6:
    text = "It is Weekend";
}

Jifunze tena

Mifano

Use switch statement to execute code block based on user input from the prompt box:

var text;
var favDrink = prompt("What's your favorite cocktail drink?");
switch(favDrink) {
  case "Martini":
    text = "Excellent choice! Martini is good for your soul.";
    break;
  case "Daiquiri":
    text = "Daiquiri is my favorite too!";
    break;
  case "Cosmopolitan":
    text = "Really? Are you sure the Cosmopolitan is your favorite?";
    break;
  default:
    text = "I have never heard of that one..";
}

Jifunze tena

Inasimamia wa kifungu

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Sayari ya kipindi

Mwongozo wa JavaScript:JavaScript If...Else Mwongozo

Mwongozo wa JavaScript:Inahatarisha ya JavaScript Switch

Mwongozo wa JavaScript:Inahatarisha ya JavaScript if/else

Mwongozo wa JavaScript:Inahatarisha ya JavaScript break