JavaScript DHTML/Language Basics/Switch
Содержание
Another switch Statement
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<HTML> <HEAD> <TITLE>Using the switch Statement</TITLE> </HEAD> <BODY> <SCRIPT LANGUAGE="JavaScript"> </SCRIPT> </BODY> </HTML>
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Switch based on integer value
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<HTML> <BODY>
<SCRIPT> var n = 1; switch (n) { case 1: { document.write("n equals 1"); break; } case 2:{ document.write("n equals 2"); break; } case 3:{ document.write("n equals 3"); break; } default:{ document.write("No match!"); break; } } </SCRIPT>
</BODY> </HTML>
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Switch statement
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/* Note that Sunday=0, Monday=1, Tuesday=2, etc.*/ <html> <body> <script type="text/javascript"> var d = new Date() theDay=d.getDay() switch (theDay){
case 5: document.write("Finally Friday") break case 6: document.write("Super Saturday") break case 0: document.write("Sleepy Sunday") break default: document.write("Not weekend!")
} </script>
</body> </html>
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Switch with string value
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<html> <head> <title></title> </head> <body> <script type="text/javascript"> var inputName = prompt("Please enter your name:"); switch(inputName) {
case "Tom": document.write("Welcome " + inputName); break; case "Name": document.write("Name"); break; default: document.write("default:" + inputName);
} </script> </body> </html>
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The switch Construction in Action
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/* JavaScript Bible, Fourth Edition by Danny Goodman John Wiley & Sons CopyRight 2001
- /
<HTML> <HEAD> <TITLE>Switch Statement and Labeled Break</TITLE> <SCRIPT LANGUAGE="JavaScript1.2"> // build two product arrays, simulating two database tables function product(name, price) {
this.name = name this.price = price
} var ICs = new Array() ICs[0] = new product("Septium 900MHz","$149") ICs[1] = new product("Septium Pro 1.0GHz","$249") ICs[2] = new product("Octium BFD 750MHz","$329") var snacks = new Array snacks[0] = new product("Rays Potato Chips","$1.79") snacks[1] = new product("Cheezey-ettes","$1.59") snacks[2] = new product("Tortilla Flats","$2.29") // lookup in the "table" associated with the product function getPrice(selector) {
var chipName = selector.options[selector.selectedIndex].text var outField = document.forms[0].cost master: switch(selector.options[selector.selectedIndex].value) { case "ICs": for (var i = 0; i < ICs.length; i++) { if (ICs[i].name == chipName) { outField.value = ICs[i].price break master } } break case "snacks": for (var i = 0; i < snacks.length; i++) { if (snacks[i].name == chipName) { outField.value = snacks[i].price break master } } break default: outField.value = "Not Found" }
} </SCRIPT> </HEAD> <BODY> Branching with the switch Statement
Select a chip for lookup in the chip price tables:
<FORM> Chip:<SELECT NAME="chips" onChange="getPrice(this)"> <OPTION> <OPTION VALUE="ICs">Septium 900MHz <OPTION VALUE="ICs">Septium Pro 1.0GHz <OPTION VALUE="ICs">Octium BFD 750MHz <OPTION VALUE="snacks">Rays Potato Chips <OPTION VALUE="snacks">Cheezey-ettes <OPTION VALUE="snacks">Tortilla Flats <OPTION>Poker Chipset </SELECT> Price:<INPUT TYPE="text" NAME="cost" SIZE=10> </FORM> </BODY> </HTML> </source>
The switch Statement
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<html> <head>
<title>The switch Statement</title>
</head> <body>
<script language="JavaScript1.2" type="text/javascript"> </script>
</body> </html>
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Use switch with true false value
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<html> <head> <title>A Simple Page</title> <script language="JavaScript"> var yourchoice; yourchoice = confirm("True of false") switch (yourchoice) {
case true: alert("true!"); break; case false: alert("false"); break;
} </script> </head> <body> </body> </html>