JavaScript DHTML/Language Basics/While

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A While Loop That Decrements from 10 to 1

  
<HTML>
<BODY>
<H1>
<SCRIPT> 
      var counter = 10; 
      while (counter > 0) 
      { 
         document.write (counter + "<br>"); 
         counter--; 
      } 
   </SCRIPT>
</H1>
</BODY>
</HTML>



Check the loop counter for while loop

 
<html>
<head>
<title></title>
</head>
<body>
<script type="text/javascript">
var i = 1;
while (i < 101) {
    if (i == 99) {
        alert("The number is " + i);
    }
    i++;
}
</script>
</body>
</html>



Do while loop

  
<html>
<body>
<script type="text/javascript">
i = 0
do{
    document.write("The number is " + i)
    document.write("<br>")
    i++
}while (i <= 5)
</script>
</body>
</html>



Do ... while loop and output calculation result

  
<html>
<head>
<title>A Simple Page</title>
<script language="JavaScript">
var x = 1
do {
    ++x;
    document.write(x+"<BR>");
}while (x < 10);
</script>
</head>
<body>
</body>
</html>



Loop in while

  
<HTML>
<HEAD>
<SCRIPT language="JavaScript">
<!-- 
count=1;
while(count<16)
{
 document.write(count+". Repetitive.<BR>");
 count+=1;
}
//-->
</SCRIPT>
</HEAD>
<BODY>
</BODY>
</HTML>



The do..while Statement Ensures at Least One Iteration

  
<html>
<head>
  <title>The do..while Statement Ensures at Least One Iteration</title>
</head>
<body>
<script language="JavaScript1.2" type="text/javascript">
  <!--
    var userEntry = 0;
    var x = 1;
   
    do{
      document.writeln(x);
      x++;
    }while(x <= userEntry);
  // -->
  </script>
</body>
</html>



The while Statement

  
<HTML>
<HEAD>
<TITLE>Using the While Statement</TITLE>
</HEAD>
<BODY>
<SCRIPT><!--
i=1
while(i<7){
 document.write("<H"+i+">This is a level "+i+" heading." +"</H"+i+">")
 ++i
}
// --></SCRIPT>
</BODY>
</HTML>



Using a Do/While Loop to Reverse a Text String

  
<HTML>
<BODY>
<H1>
<SCRIPT> 
      var newString = ""; 
      var theString = "string"; 
      var counter = theString.length; 
      do 
      { 
        newString += theString.substring(counter-1, counter); 
        counter--; 
      } 
      while (counter > 0 ); 
      document.write(theString + " reversed is " + newString + "!"); 
   </SCRIPT>
</H1>
</BODY>
</HTML>



Using the while Loop in JavaScript

  
<html>
<head>
  <title>Using the while Loop in JavaScript</title>
</head>
<body>
  <script type="text/javascript">
  <!--
    var i = 0;
    var result = 0;
    var status = true;
   
    document.write("0");
    while(status){
      result += ++i;
      document.write(" + " + i);
      if(i == 10){
        status = false;
      }
    }
    document.writeln(" = " + result);
    // -->
  </script>
</body>
</html>



While loop

  
<html>
<body>
<script type="text/javascript">
i = 0
while (i <= 5){
    document.write("The number is " + i)
    document.write("<br>")
    i++
}
</script>
</body>
</html>



While loop test

  
<html>
<script language="JavaScript">
<!--
function loopTest() {
    var index = 1;
    while (index <= 12) {
          if (index == 6)
             break;
          index++;
    }
    document.write("The break statement brings us here.");
}
loopTest();
//-->
</script>
</html>
Источник — «http://wbex.ru/index.php?title=JavaScript_DHTML/Language_Basics/While&oldid=3104»