JavaScript DHTML/Language Basics/throw — различия между версиями

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м (1 версия)
 
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Текущая версия на 07:24, 26 мая 2010

Catch that error

   
<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>



Exception handling with try/catch

   
<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>



Throws error in case of invalid data

  

<html>
<head>
<title>Try/Catch</title>
</head>
<body>
<form name="formexample" id="formexample" action="#">
<div id="valueDiv">Enter a value: <input id="value" name="value"></div>
<div><input id="submit" type="submit"></div>
</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>



Throw that error

   
<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>
Источник — «http://wbex.ru/index.php?title=JavaScript_DHTML/Language_Basics/throw&oldid=3115»