JavaScript Tutorial/Function/Function Return
Содержание
return
The return keyword will exit the existing function and return a value.
<html>
<body>
<script language="JavaScript">
<!--
function getValue(){
var myValue = 4*3;
return myValue;
}
function fill(){
var x = getValue();
document.form1.tmp.value = x;
}
-->
</script>
<form name="form1">
Value: <input type="text" Name="tmp" Size=5>
<br>
<br>
<input type="button" name="get" value="Get Returned Value" onClick="fill()">
<br>
<br>
</form>
</body>
</html>
Return an array from a function
<HTML>
<HEAD>
<TITLE>
Iteration Two
</TITLE>
<SCRIPT>
function makeArray() {
var myArray = new Array(4);
myArray[0] = "A";
myArray[1] = "B";
myArray[2] = "C";
myArray[3] = "D";
return myArray;
}
function showArray(theArray){
var quote = "";
for (var i = 0; i < theArray.length; i++){
quote += theArray[i] + " ";
}
return quote;
}
</SCRIPT>
</HEAD>
<BODY>
<H1>
<SCRIPT>
var x = makeArray();
document.write(showArray(x));
</SCRIPT>
</H1>
</BODY>
</HTML>
Return boolean value from function
<html>
<head>
<script Language="Javascript" type = "text/javascript">
<!--
var newurl
function CheckRequest(newurl)
{
if (confirm("Do you want to visit " + newurl + " site.")) {
return true;
} else {
return false;
}
}
//-->
</script>
<title>Capturing Links</title>
</head>
<P><A href="http://www.wbex.ru" onClick = "return CheckRequest("wbex")">Java</A></P>
<P><A href="http://www.netscape.ru" onClick = "return CheckRequest("Netscape")">Netscape</A></P>
</body>
</html>
Returning Values
JavaScript provides a return statement to return a value.
The value to be returned is placed after the keyword return.
The "undefined" value is returned from a function if no value is specified after the keyword return or if the return statement is not used.
A value returned from a function can be assigned to a variable or used within an expression.
<html>
<SCRIPT LANGUAGE="JavaScript">
<!--
function multiplyByFive(aNumber)
{
return aNumber*5;
}
document.write("3*5=",multiplyByFive(3));
//-->
</SCRIPT>
</html>
Return value from a function
<html>
<head>
<title>A Simple Page</title>
<script language="JavaScript">
<!--
function calcAvg()
{
var inpNum1 = 1;
var inpNum2 = 2;
var inpNum3 = 3;
var inpNum4 = 4;
numAvg = doCalcAvg(inpNum1, inpNum2, inpNum3, inpNum4);
document.write("The average of the four numbers you entered is: " + numAvg);
}
function doCalcAvg(inpNum1, inpNum2, inpNum3, inpNum4)
{
var ans;
ans = (Number(inpNum1) + Number(inpNum2) + Number(inpNum3) + Number(inpNum4)) / 4;
return (ans);
}
// -->
</script>
</head>
<body onLoad="calcAvg();">
</body>
</html>