JS Object-Oriented Learning Note II (Debug debugging method)

1. JS Debugging

Obviously, JS debugging can only be printed with alert

alert (ID);

for complex data types, we can then eject them by converting them to JSON format

Alert (json.stringify (data));

2. DOM Information Debugging
For the information we need to get, we can print it to the DOM element as required.

document.write (data); Will overwrite the entire document

3. Debugging at the terminal
Exit after printing the required information directly on the terminal

Var_dump () Print_r ()

4. JS other error information processing

/*================== most browsers support a small subset of =====================*/window.onerror=handleerrfunction HANDLEERR (msg,url,l) that are not supported {    txt= "there was a error on this page.\n\n"    txt+= "error:" + msg + "\ n"    txt+= "url:" + URL + "\ n"    txt+= "L INE: "+ L +" \ n "    txt+=" click OK to continue.\n\n "    alert (TXT)    return true;}

5. Try Catch debugging

/*================== browsers support ====================*/    try{      adddlert ("Welcome guest!");    }    catch (Err) {          txt= "This page has an error. \ n ";          txt+= "Error Description:" + err.message + "\ n";          txt+= "Click OK to continue. \ n ";          alert (TXT);   }

6. Of course we can use Console.log if we check for errors on the PC-side browser

Console.log (data);

JS Object-Oriented Learning Note II (Debug debugging method)