JavaScript, estartando Comentários e Blocos:
JavaScript statements
<!DOCTYPE html>
<html>
<body>
<h1>My Web Page</h1>
<p id="demo">A Paragraph.</p>
<div id="myDIV">A DIV.</div>
<script>
document.getElementById("demo").innerHTML="Hello Dolly";
document.getElementById("myDIV").innerHTML="How are you?";
</script>
</body>
</html>
Resultado no Navegador:
My Web Page
Hello Dolly
How are you?
JavaScript blocks
<!DOCTYPE html>
<html>
<body>
<h1>My Web Page</h1>
<p id="myPar">I am a paragraph.</p>
<div id="myDiv">I am a div.</div>
<p>
<button type="button" onclick="myFunction()">Try it</button>
</p>
<script>
function myFunction()
{
document.getElementById("myPar").innerHTML="Hello Dolly";
document.getElementById("myDiv").innerHTML="How are you?";
}
</script>
<p>When you click on "Try it", the two elements will change.</p>
</body>
</html>
Resultado no Navegador:
I am a paragraph.
I am a div.
When you click on "Try it", the two elements will change.
Comentários de Linha:
<!DOCTYPE html>
<html>
<body>
<h1 id="myH1"></h1>
<p id="myP"></p>
<script>
// Write to a heading:
document.getElementById("myH1").innerHTML="Welcome to my Homepage";
// Write to a paragraph:
document.getElementById("myP").innerHTML="This is my first paragraph.";
</script>
<p><strong>Note:</strong> The comments are not executed.</p>
</body>
</html>
Resultado no Navegador:
Welcome to my Homepage
This is my first paragraph.
Note: The comments are not executed.Simples linha de comentários:
<!DOCTYPE html>
<html>
<body>
<h1 id="myH1"></h1>
<p id="myP"></p>
<script>
// Write to a heading:
document.getElementById("myH1").innerHTML="Welcome to my Homepage";
// Write to a paragraph:
document.getElementById("myP").innerHTML="This is my first paragraph.";
</script>
<p><strong>Note:</strong> The comments are not executed.</p>
</body>
</html>
Resultado no Navegador:
Welcome to my Homepage
This is my first paragraph.
Note: The comments are not executed.Multiplos comentários de linha:
<!DOCTYPE html>
<html>
<body>
<h1 id="myH1"></h1>
<p id="myP"></p>
<script>
// Write to a heading:
document.getElementById("myH1").innerHTML="Welcome to my Homepage";
// Write to a paragraph:
document.getElementById("myP").innerHTML="This is my first paragraph.";
</script>
<p><strong>Note:</strong> The comments are not executed.</p>
</body>
</html>
Resultado no Navegador:
Welcome to my Homepage
This is my first paragraph.
Note: The comments are not executed.Comentário de linha única para impedir a execução.
<!DOCTYPE html>
<html>
<body>
<h1 id="myH1"></h1>
<p id="myP"></p>
<script>
//document.getElementById("myH1").innerHTML="Welcome to my Homepage";
document.getElementById("myP").innerHTML="This is my first paragraph.";
</script>
<p><strong>Note:</strong> The comment is not executed.</p>
</body>
</html>
Resultado no Navegador:
This is my first paragraph.
Note: The comment is not executed.Várias linhas comentadas para impedir a execução
<!DOCTYPE html>
<html>
<body>
<h1 id="myH1"></h1>
<p id="myP"></p>
<script>
/*
document.getElementById("myH1").innerHTML="Welcome to my Homepage";
document.getElementById("myP").innerHTML="This is my first paragraph.";
*/
</script>
<p><strong>Note:</strong> The comment-block is not executed.</p>
</body>
</html>
Resultado no Navegador:
Note: The comment-block is not executed.
Fonte:.w3schools.com
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