Hoisting ﺖﭙﯾﺮﮑﺳﺍ ﺍﻭﺎﺟ

فهرست مطالب

Hoisting ﺶﯿﭘ ﺭﺎﺘﻓﺭﻥﻼﻋﺍ ﻝﺎﻘﺘﻧﺍ ﯼﺍﺮﺑ ﺖﭙﯾﺮﮑﺳﺍ ﺍﻭﺎﺟ ﺽﺮﻓﺖﺳﺍ ﻥﺁ ﻪﺑ ﺎﻫ

ﺖﺳﺍ ﻪﺘﻓﺎﯾ ﺶﯾﺍﺰﻓﺍ ﺖﭙﯾﺮﮑﺳﺍ ﺍﻭﺎﺟ ﯼﺎﻫ ﻪﯿﻣﻼﻋﺍ

.ﺩﺮﮐ ﻡﻼﻋﺍ ﻥﺁ ﺯﺍ ﻩﺩﺎﻔﺘﺳﺍ ﺯﺍ ﺲﭘ ﻥﺍﻮﺗ ﯽﻣ ﺍﺭ ﺮﯿﻐﺘﻣ ﮏﯾ ،ﺖﭙﯾﺮﮑﺳﺍ ﺍﻭﺎﺟ ﺭﺩ

.ﺩﺮﮐ ﻩﺩﺎﻔﺘﺳﺍ ﻡﻼﻋﺍ ﺯﺍ ﻞﺒﻗ ﻥﺍﻮﺗ ﯽﻣ ﺍﺭ ﺮﯿﻐﺘﻣ ﮏﯾ ؛ﺮﮕﯾﺩ ﺕﺭﺎﺒﻋ ﻪﺑ

1 ﻝﺎﺜﻣ ﻪﺑ ﺍﺭ ﻪﺠﯿﺘﻧ ﻥﺎﻤﻫ 2 ﻝﺎﺜﻣ ﺪﻫﺩ ﯽﻣ:

1 ﻝﺎﺜﻣ

x = 5; // Assign 5 to x

elem = document.getElementById("demo"); // Find an element 
elem.innerHTML = x;                     
// Display x in the element
var x; // Declare x

→ ﺪﯿﻨﮐ ﻥﺎﺤﺘﻣﺍ ﺍﺭ ﻥﺁ ﻥﺎﺗﺩﻮﺧ

<!DOCTYPE html>
<html>
<body>

<p id="demo"></p>

<script>
x = 5; // Assign 5 to x

elem = document.getElementById("demo"); // Find an element 
elem.innerHTML = x;           // Display x in the element

var x; // Declare x
</script>

</body>
</html>

2 ﻝﺎﺜﻣ

var x; // Declare x
x = 5; // Assign 5 to x

elem = document.getElementById("demo"); // Find an element 
elem.innerHTML = x;                     
// Display x in the element

→ ﺪﯿﻨﮐ ﻥﺎﺤﺘﻣﺍ ﺍﺭ ﻥﺁ ﻥﺎﺗﺩﻮﺧ

<!DOCTYPE html>
<html>
<body>

<p id="demo"></p>

<script>
var x; // Declare x
x = 5; // Assign 5 to x

elem = document.getElementById("demo"); // Find an element 
elem.innerHTML = x;           // Display x in the element
</script>

</body>
</html>

.ﺪﯿﻨﮐ ﮎﺭﺩ ﺍﺭ "ﻥﺩﺮﺑ ﻻﺎﺑ" ﺡﻼﻄﺻﺍ ﺪﯾﺎﺑ ،ﻉﻮﺿﻮﻣ ﻦﯾﺍ ﮎﺭﺩ ﯼﺍﺮﺑ

Hoisting ﺶﯿﭘ ﺭﺎﺘﻓﺭﻥﻼﻋﺍ ﻪﻤﻫ ﻝﺎﻘﺘﻧﺍ ﯼﺍﺮﺑ ﺖﭙﯾﺮﮑﺳﺍ ﺍﻭﺎﺟ ﺽﺮﻓﺖﺳﺍ ﻥﺁ ﻪﺑ ﺎﻫ

const ﻭ let ﯼﺪﯿﻠﮐ ﺕﺎﻤﻠﮐ

.ﺪﻧﺮﯿﮔﯽﻣ ﺭﺍﺮﻗ ﻻﺎﺑ ﺭﺩ ﺪﻧﺍﻩﺪﺷ ﻒﯾﺮﻌﺗ const ﻭ

ﺩﺭﺍﺩ ﺭﺍﺮﻗ "ﯽﻧﺎﻣﺯ ﻩﺩﺮﻣ ﻪﻘﻄﻨﻣ" ﺭﺩ ﺍﺪﺘﺑﺍ ﺯﺍ ﺮﯿﻐﺘﻣ

ﻝﺎﺜﻣ

carName = "Volvo";
let carName;

→ ﺪﯿﻨﮐ ﻥﺎﺤﺘﻣﺍ ﺍﺭ ﻥﺁ ﻥﺎﺗﺩﻮﺧ

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript Hoisting</h2>
<p>With <b>let</b>, you cannot use a variable before it is declared.</p>
<p id="demo"></p>

<script>
try {
  carName = "Saab";
  let carName = "Volvo";
}
catch(err) {
  document.getElementById("demo").innerHTML = err;
}
</script>

</body>
</html>

.ﺖﺳﺍ ﯼﻮﺤﻧ ﯼﺎﻄﺧ ﮏﯾ ،ﻡﻼﻋﺍ ﺯﺍ ﻞﺒﻗ const ﺮﯿﻐﺘﻣ ﺯﺍ ﻩﺩﺎﻔﺘﺳ

ﻝﺎﺜﻣ

.ﺩﻮﺷ ﯽﻤﻧ ﺍﺮﺟﺍ ﺪﮐ ﻦﯾﺍ

carName = "Volvo";
const carName;

→ ﺪﯿﻨﮐ ﻥﺎﺤﺘﻣﺍ ﺍﺭ ﻥﺁ ﻥﺎﺗﺩﻮﺧ

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript Hoisting</h2>

<p>With <b>const</b>, you cannot use a variable before it is declared.</p>
<p>Try to remove the //.</p>

<p id="demo"></p>

<script>
carName = "Volvo";
//const carName;
document.getElementById("demo").innerHTML = carName;
</script>

</body>
</html>

.ﺪﯿﻧﺍﻮﺨﺑ ﺮﺘﺸﯿﺑ JS Let/Const ﺭﺩ const ﻭ let ﻩﺭﺎﺑﺭﺩ

ﺩﻭﺭ ﯽﻤﻧ ﻻﺎﺑ ﺖﭙﯾﺮﮑﺳﺍ ﺍﻭﺎﺟ ﻪﯿﻟﻭﺍ ﯽﻫﺩﺭﺍﺪﻘﻣ

.ﻪﯿﻟﻭﺍ ﯽﻫﺩﺭﺍﺪﻘﻣ ﻪﻧ ،ﺪﻫﺩ ﯽﻣ ﺶﯾﺍﺰﻓﺍ ﺍﺭ ﺎﻫ ﻥﻼﻋﺍ ﻂﻘﻓ ﺖﭙﯾﺮﮑﺳﺍ ﺍﻭﺎﺟ

1 ﻝﺎﺜﻣ ﺍﺭ ﻪﺠﯿﺘﻧ ﻥﺎﻤﻫ ﯽﻤﻧ ﺪﻫﺩ ﯽﻣ

1 ﻝﺎﺜﻣ

var x = 5; // Initialize x
var y = 7; // Initialize y
elem = document.getElementById("demo"); // Find an element 
elem.innerHTML = x + " " + y;           // Display x and y

→ ﺪﯿﻨﮐ ﻥﺎﺤﺘﻣﺍ ﺍﺭ ﻥﺁ ﻥﺎﺗﺩﻮﺧ

<!DOCTYPE html>
<html>
<body>

<p id="demo"></p>

<script>
var x = 5; // Initialize x
var y = 7; // Initialize y

elem = document.getElementById("demo"); // Find an element 
elem.innerHTML = x + " " + y;       // Display x and y

</script>

</body>
</html>

2 ﻝﺎﺜﻣ

var x = 5; // Initialize x

elem = document.getElementById("demo"); // Find an element 
elem.innerHTML = x + " " + y;           // Display x and y

var y = 7; // Initialize y

→ ﺪﯿﻨﮐ ﻥﺎﺤﺘﻣﺍ ﺍﺭ ﻥﺁ ﻥﺎﺗﺩﻮﺧ

<!DOCTYPE html>
<html>
<body>

<p id="demo"></p>

<script>
var x = 5;  // Initialize x

elem = document.getElementById("demo");      // Find an element 
elem.innerHTML = "x is " + x + " and y is " + y;  // Display x and y

var y = 7;  // Initialize y
</script>

</body>
</html>

؟ﺪﺷﺎﺑ ﻩﺪﺸﻧ ﻒﯾﺮﻌﺗ ﺮﺧﺁ ﻝﺎﺜﻣ ﺭﺩ y ﻪﮐ ﺖﺳﺍ ﯽﻘﻄﻨﻣ ﺎﯾﺁ

.ﺩﻭﺭ ﯽﻣ ﻻﺎﺑ ﻻﺎﺑ ﻪﺑ (7=) ﻪﯿﻟﻭﺍ ﯽﻫﺩ ﺭﺍﺪﻘﻣ ﻪﻧ ﻭ (var y) ﻥﻼﻋﺍ ﻂﻘﻓ ﻪﮐ ﺖﺳﺍ ﻞﯿﻟﺩ ﻦﯾﺍ ﻪﺑ ﻦﯾﺍ

ﻞﯿﻟﺩ ﻪﺑ ﺎﻣﺍ ،ﺖﺳﺍ ﻩﺪﺷ ﻡﻼﻋﺍ ﻩﺩﺎﻔﺘﺳﺍ ﺯﺍ ﻞﺒﻗ y ،ﻥﺩﺮﺑ ﻻﺎﺑ ﻞﯿﻟﺩ ﻪﺑ

:ﺖﺳﺍ ﻦﺘﺷﻮﻧ ﺪﻨﻧﺎﻣ 2 ﻝﺎﺜﻣ

ﻝﺎﺜﻣ

var x = 5; // Initialize x
var y;     // Declare y

elem = document.getElementById("demo"); // Find an element 
elem.innerHTML = x + " " + y;           // Display x and y

y = 7;    // Assign 7 to y

→ ﺪﯿﻨﮐ ﻥﺎﺤﺘﻣﺍ ﺍﺭ ﻥﺁ ﻥﺎﺗﺩﻮﺧ

<!DOCTYPE html>
<html>
<body>

<p id="demo"></p>

<script>
var x = 5; // Initialize x
var y;   // Declare y

elem = document.getElementById("demo"); // Find an element 
elem.innerHTML = x + " " + y;       // Display x and y

y = 7;   // Assign 7 to y

</script>

</body>
</html>

!ﺪﯿﻨﮐ ﻡﻼﻋﺍ ﻻﺎﺑ ﺭﺩ ﺍﺭ ﺩﻮﺧ ﯼﺎﻫﺮﯿﻐﺘﻣ

ﺖﺳﺍ ﻩﺪﺷ ﻪﺘﻓﺮﮔ ﻩﺪﯾﺩﺎﻧ ﺎﯾ ﻪﺘﺧﺎﻨﺷﺎﻧ ﺭﺎﺘﻓﺭ ﮏﯾ (ﻥﺎﮔﺪﻨﻫﺩ ﻪﻌﺳﻮﺗ ﺯﺍ ﯼﺭﺎﯿﺴﺑ ﯼﺍﺮﺑ) ﻥﺩﺮﺑ ﻻﺎﺑ

<p>.ﺪﻨﺷﺎﺑ (ﺎﻄﺧ) ﺕﻻﺎﮑﺷﺍ ﯼﺍﺭﺍﺩ ﺎﻫﻪﻣﺎﻧﺮﺑ ﺖﺳﺍ ﻦﮑﻤﻣ ،ﺩﻮﺸﻧ ﻪﺟﻮﺘﻣ ﺍﺭ ﻥﺩﺮﺑ ﻻﺎﺑ ﻩﺪﻨﻫﺩ

ﺪﻧﻮﺷ ﻩﺩﺎﻔﺘﺳﺍ ﺎﻬﻧﺁ ﺯﺍ ﻩﺩﺎﻔﺘﺳﺍ ﺕﺭﻮﺻ ﺭﺩ ﺎﻫﺮﯿﻐﺘﻣ ﻪﮐ ﺪﻫﺩ ﯽﻤﻧ ﻩﺯﺎﺟﺍ ﺖﺨﺳ ﺖﻟﺎﺣ ﺭﺩ ﺖﭙﯾﺮﮑﺳﺍ ﺍﻭﺎ