JavaScript-verklarings-verwysing
JavaScript-verklarings
In HTML is JavaScript-stellings "instruksies" wat deur die webblaaier "uitgevoer" moet word.
Hierdie stelling vertel die blaaier om "Hallo Dolly" te skryf. binne 'n HTML-element met id="demo":
Voorbeeld
document.getElementById("demo").innerHTML = "Hello Dolly.";
Vir 'n tutoriaal oor stellings, lees ons JavaScript-verklarings-tutoriaal .
JavaScript-verklaring-identifiseerders
JavaScript-stellings begin dikwels met 'n stellingidentifiseerder om die JavaScript-aksie te identifiseer wat uitgevoer moet word.
Stellingidentifiseerders is gereserveerde woorde en kan nie as veranderlike name (of enige ander dinge) gebruik word nie.
Die volgende tabel lys alle JavaScript-stellingidentifiseerders:
Statement | Description |
---|---|
break | Exits a switch or a loop |
class | Declares a class |
const | Declares a variable with a constant value |
continue | Breaks one iteration (in the loop) if a specified condition occurs, and continues with the next iteration in the loop |
debugger | Stops the execution of JavaScript, and calls (if available) the debugging function |
do ... while | Executes a block of statements and repeats the block while a condition is true |
for | Loops through a block of code a number of times |
for ... in | Loops through the properties of an object |
for ... of | Loops through the values of an iterable object |
function | Declares a function |
if ... else ... else if | Marks a block of statements to be executed depending on a condition |
let | Declares a variable |
return | Stops the execution of a function and returns a value from that function |
switch | Marks a block of statements to be executed depending on different cases |
throw | Throws (generates) an error |
try ... catch ... finally | Marks the block of statements to be executed when an error occurs in a try block, and implements error handling |
var | Declares a variable |
while | Marks a block of statements to be executed while a condition is true |