js中的自定义异常处理函数
1.?Can I suppress JavaScript error messages?
2.?Can I set up my own JavaScript error handler?
3.?Can I change the active JavaScript error handler??(Demo)
Question:?Can I suppress JavaScript error messages?
Answer:?Yes – although usually it is not a good design decision to do so. (Normally, you are much better off?fixing?the errors, rather than just suppressing the error messages.)
To suppress all JavaScript error messages on your HTML page, you can put the following script code in the?<HEAD>?section of your page:
<SCRIPT language="JavaScript"> <!-- function silentErrorHandler() {return true;} window.οnerrοr=silentErrorHandler; //--> </SCRIPT>Or you can use a similar code fragment (without the?SCRIPT?tags) in an included?.js?file, if you have one. For a working code example, see this?error handling demo!
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Question:?Can I set up my own JavaScript error handler?
Answer:?Yes. To define your own error handler, use this JavaScript code:
function handlerFunction(description,page,line) {// put error-handling operators herereturn true; } window.οnerrοr=handlerFunction;Your error handler function can optionally use the following parameters:
- a textual description of the error
- the address (URL) of the page on which the error occurred
- the number of the line in which the error occurred
The error handler function must return?false?if you wish to invoke the browser's default error handler after your own handler finishes. If you don't want to invoke the browser's default handler, your handler function must return?true. For an additional code example, check out this?error handling demo!
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Question:?Can I dynamically change the JavaScript error handler?
Answer:?Yes. To change the JavaScript error handler, just setwindow.onerror?to the name of the function that will serve as your new error handler.
Here's a demo that lets you test three different error handlers:
- the browser's default error handler
- an error handler that displays a customized?alert box
- a "silent" error handler that suppresses all error messages.? Custom Error Handler?Silent Error Handler?Default Error Handler??
- Use the select box to set or change the error handler.
- Click?Fire an Error?to test the active error handler.
Below is the source code of the error handling functions used in this demo:
function defaultHandler() {return false} function silentHandler() {return true} function customHandler(desc,page,line,chr) {alert('JavaScript error occurred! \n'+'The error was handled by '+'a customized error handler.\n'+'\nError description: \t'+desc+'\nPage address: \t'+page+'\nLine number: \t'+line)return true }?
轉載于:https://www.cnblogs.com/oxspirt/p/6700974.html
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