How do I debug JavaScript in a WebBrowser control?
in [VB.NET]
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From: John Brock on 14 Sep 2009 15:26 I am using Visual Basic 2008 Express to write a Windows Forms application that displays HTML/JavaScript pages in a WebBrowser control. (I'm setting the form as the WebBrowser's ObjectForScripting and calling "window.external.whatever()" from JavaScript when I want JavaScript to call functions in the app). Right now it can be very difficult to find bugs in the JavaScript code. If I set ScriptErrorsSuppressed = False I sometimes get a helpful popup. Or I can scatter JavaScript alert popups through the code. But it would be very nice to have a real debugger! So I'm trying to find out if there are any standard (or even non-standard) ways to debug JavaScript in this situation. (Note that I have IE8 installed on my PC. I understand there is a spiffy new JavaScript debugger that comes with IE8 -- it's part of the Developer Tools that pop up if I hit F12 while in IE. It would be very nice to be able to use this to set breakpoints in pages displayed in the WebBrowser, but there is no obvious way to do this, as F12 does nothing here). -- John Brock jbrock(a)panix.com
From: Ralph on 14 Sep 2009 15:37 On Sep 14, 3:26 pm, jbr...(a)panix.com (John Brock) wrote: > I am using Visual Basic 2008 Express to write a Windows Forms > application that displays HTML/JavaScript pages in a WebBrowser > control. (I'm setting the form as the WebBrowser's ObjectForScripting > and calling "window.external.whatever()" from JavaScript when I > want JavaScript to call functions in the app). > > Right now it can be very difficult to find bugs in the JavaScript > code. If I set ScriptErrorsSuppressed = False I sometimes get a > helpful popup. Or I can scatter JavaScript alert popups through > the code. But it would be very nice to have a real debugger! So > I'm trying to find out if there are any standard (or even non-standard) > ways to debug JavaScript in this situation. > > (Note that I have IE8 installed on my PC. I understand there is > a spiffy new JavaScript debugger that comes with IE8 -- it's part > of the Developer Tools that pop up if I hit F12 while in IE. It > would be very nice to be able to use this to set breakpoints in > pages displayed in the WebBrowser, but there is no obvious way to > do this, as F12 does nothing here). > -- > John Brock > jbr...(a)panix.com try putting the following into your javascript code. debugger;
From: John Brock on 14 Sep 2009 18:11 In article <cab85f56-cbca-465b-a7f7-578c5ae73946(a)g6g2000vbr.googlegroups.com>, Ralph <ralphd42(a)gmail.com> wrote: >On Sep 14, 3:26�pm, jbr...(a)panix.com (John Brock) wrote: >> I am using Visual Basic 2008 Express to write a Windows Forms >> application that displays HTML/JavaScript pages in a WebBrowser >> control. �(I'm setting the form as the WebBrowser's ObjectForScripting >> and calling "window.external.whatever()" from JavaScript when I >> want JavaScript to call functions in the app). >> >> Right now it can be very difficult to find bugs in the JavaScript >> code. �If I set ScriptErrorsSuppressed = False I sometimes get a >> helpful popup. �Or I can scatter JavaScript alert popups through >> the code. �But it would be very nice to have a real debugger! �So >> I'm trying to find out if there are any standard (or even non-standard) >> ways to debug JavaScript in this situation. >> >> (Note that I have IE8 installed on my PC. �I understand there is >> a spiffy new JavaScript debugger that comes with IE8 -- it's part >> of the Developer Tools that pop up if I hit F12 while in IE. �It >> would be very nice to be able to use this to set breakpoints in >> pages displayed in the WebBrowser, but there is no obvious way to >> do this, as F12 does nothing here). >try putting the following into your javascript code. > >debugger; Thanks for the suggestion. I already tried that though (forgot to mention it), and it doesn't seem to have any effect, at least not from within a WebBrowser control. (Interestingly, uncaught exceptions in my VB.NET code don't cause the program to terminate when they occur as a result of JavaScript calling a function in the app, so I have to explicitly catch and display them if I want to see them. I wonder if that means anything?) -- John Brock jbrock(a)panix.com
From: Scott M. on 14 Sep 2009 19:13 It's a bit of a hack, but you could insert a JavaScript alert(); within the document to display pertinent info helpful for debugging. -Scott "John Brock" <jbrock(a)panix.com> wrote in message news:h8m5dq$3p9$1(a)reader1.panix.com... >I am using Visual Basic 2008 Express to write a Windows Forms > application that displays HTML/JavaScript pages in a WebBrowser > control. (I'm setting the form as the WebBrowser's ObjectForScripting > and calling "window.external.whatever()" from JavaScript when I > want JavaScript to call functions in the app). > > Right now it can be very difficult to find bugs in the JavaScript > code. If I set ScriptErrorsSuppressed = False I sometimes get a > helpful popup. Or I can scatter JavaScript alert popups through > the code. But it would be very nice to have a real debugger! So > I'm trying to find out if there are any standard (or even non-standard) > ways to debug JavaScript in this situation. > > (Note that I have IE8 installed on my PC. I understand there is > a spiffy new JavaScript debugger that comes with IE8 -- it's part > of the Developer Tools that pop up if I hit F12 while in IE. It > would be very nice to be able to use this to set breakpoints in > pages displayed in the WebBrowser, but there is no obvious way to > do this, as F12 does nothing here). > -- > John Brock > jbrock(a)panix.com >
From: John Brock on 15 Sep 2009 15:56
I'm already using alert(), but a real debugger would be extremely desirable. I'm sure the people doing ASP.NET programming aren't using alert() -- (which is why I included an ASP.NET newsgroup in my distribution list) -- but I have no idea if what they are doing is applicable to me. Maybe if I were using a full version of Visual Studio, rather than VB Express? But displaying JavaScript in a WebBrowser control has got to be a fairly common practice, so I'm really hoping there is something out there I can use. In article <O1eULDZNKHA.4816(a)TK2MSFTNGP04.phx.gbl>, Scott M. <s-mar(a)nospam.nospam> wrote: >It's a bit of a hack, but you could insert a JavaScript alert(); within the >document to display pertinent info helpful for debugging. >"John Brock" <jbrock(a)panix.com> wrote in message >news:h8m5dq$3p9$1(a)reader1.panix.com... >>I am using Visual Basic 2008 Express to write a Windows Forms >> application that displays HTML/JavaScript pages in a WebBrowser >> control. (I'm setting the form as the WebBrowser's ObjectForScripting >> and calling "window.external.whatever()" from JavaScript when I >> want JavaScript to call functions in the app). >> >> Right now it can be very difficult to find bugs in the JavaScript >> code. If I set ScriptErrorsSuppressed = False I sometimes get a >> helpful popup. Or I can scatter JavaScript alert popups through >> the code. But it would be very nice to have a real debugger! So >> I'm trying to find out if there are any standard (or even non-standard) >> ways to debug JavaScript in this situation. >> >> (Note that I have IE8 installed on my PC. I understand there is >> a spiffy new JavaScript debugger that comes with IE8 -- it's part >> of the Developer Tools that pop up if I hit F12 while in IE. It >> would be very nice to be able to use this to set breakpoints in >> pages displayed in the WebBrowser, but there is no obvious way to >> do this, as F12 does nothing here). -- John Brock jbrock(a)panix.com |