JavaScript DHTML/Language Basics/throw
Содержание
Catch that error
<source lang="html4strict">
<HTML> <HEAD> <TITLE>Catch that error!</TITLE> <SCRIPT> function catchError(errString) {
try {
try {
if (errString == -1)
throw new Error (-1, "errString is -1!");
else
throw new Error (0, "errString is NOT -1!");
}
catch(e) {
if (e.number == -1)
return (e.description + " Got this one!");
else
throw e;
}
}
catch (e){
return(e.description + " This one not handled here!");
}
} </SCRIPT> </HEAD> <BODY> <FORM name="theForm"> <INPUT type=text name=errText value="-1"> <INPUT type=button name=btnThrow value="Catch it!" onClick="alert(catchError(document.theForm.errText.value));"> </FORM> </BODY> </HTML>
</source>
Exception handling with try/catch
<source lang="html4strict">
<HTML> <HEAD> <TITLE></TITLE> <SCRIPT LANGUAGE="JavaScript" TYPE="text/javascript"> function getMonthName (monthNumber) {
throw "InvalidMonthNumber"
} try {
alert(getMonthName(13))
} catch (exception) {
alert("An " + exception + " exception was encountered. Please contact the program vendor.")
}
</SCRIPT> <BODY> </BODY> </HTML>
</source>
Throws error in case of invalid data
<source lang="html4strict">
<html> <head> <title>Try/Catch</title> </head> <body> <form name="formexample" id="formexample" action="#">
</form> <script type="text/javascript"> function checkValid() {
try {
var valueField = document.forms[0]["value"];
if (valueField.value != "A") {
throw "It"s not what I need";
}
}
catch(errorObject) {
alert(errorObject);
}
} function init() {
document.forms[0].onsubmit = function() { return checkValid() };
} window.onload = init; </script> </body> </html>
</source>
Throw that error
<source lang="html4strict">
<HTML> <HEAD> <TITLE>Throw that error!</TITLE> <SCRIPT> function throwError(errString) {
try {
throw new Error (42, errString);
}
catch(e){
alert("Error number: " + e.number + "; Description: " + e.description)
}
} </SCRIPT> </HEAD> <BODY> <FORM name="theForm"> Error text: <INPUT type=text name=errText size=40> <INPUT type=button name=btnThrow value="Throw it!" onClick="throwError(document.theForm.errText.value);"> </FORM> </BODY> </HTML>
</source>
