Detailed explanation of calling custom JS methods on the server side (Page.Write)_javascript skills

First of all, we should be able to clarify why we use Page.Write to output the custom JS method to the page and why IE cannot recognize it and an "XXX is not defined" error will appear. The reason is simple, because the script we output using Page.Write appears at the top of the page. When IE reads that it is a javascript function, it starts executing it. However, the js file we linked to is not read by IE at this time, so IE cannot recognize the method we defined in the js file. Then why is write alert possible? Because alert is a script function embedded in IE, IE will recognize it regardless of whether there is a page or not.
Find the problem and it will be solved naturally:
1. Embed our customized method into IE. ---> It looks a bit whimsical, haha ​​
2. Wait until the page is loaded before triggering the event. --->Trigger event, that's right.
How to know if the page is loaded?
1. Through document status
2. Through event triggering (windows.onload)
The first one seems to be less safe. Sometimes it is clear that all the files have been loaded, but it still keeps showing the message "Transmitting data" (FF). This situation is the most obvious), so it is safer to use events.
Define a simple method, mount it in windows.onload, and make a mark when executing

Copy the code The code is as follows :

var loadComplete = false;
function LoadCompleted()
{
loadComplete= true;
}
window.attachEvent("onload",LoadCompleted) ;

Haha, in this way we only need to determine whether the page has been loaded by judging loadComplete.

Copy code The code is as follows:

var mImgdir = "";
var mCaption = "caption";
var mMsg = "Message";
var mOkClick= null;
function ShowMessage(imgdir,caption,msg,OkClick)
{
if(loadComplete)
{
KMessageBox.ShowInfo(mImgdir,mCaption,mMsg,mOkClick);
}
}

In this way, we will not execute it when loadComplete is not false. KMessageBox.ShowInfo() method, as long as there will be no JS error prompt.
This alone is not enough, because IE only executes the output script once when outputting the page, but at this time loadComplete=false, so we need to regularly detect whether the page has been loaded. When it comes to timing, we just use setTimeout & setInterval. We need constant detection here, so we use the setInterval method. The final code is as follows:

Copy code The code is as follows:

var loadComplete = false;
var mImgdir = "";
var mCaption = "caption";
var mMsg = "Message";
var mOkClick= null;
var timerID;
function ShowMessage(imgdir,caption, msg,OkClick)
{
if(loadComplete)
{
KMessageBox.ShowInfo(mImgdir,mCaption,mMsg,mOkClick);
//Unload this event window.detachEvent("onload" ,function(){LoadCompleted;}); //Stop timing trigger
window.clearInterval(timerID);
}
}
function LoadCompleted() { loadComplete=true; }
window .attachEvent("onload",LoadCompleted);
//Set the timing detection mechanism
timerID = window.setInterval(ShowMessage,1);

Of course the above code is only compatible with IE, because Use attachEvent and detachEvent. As for making it compatible with other browsers, please refer to [JavaScript] Customizing Title Display Method for the treatment method:

Copy code The code is as follows:

if(!document.attachEvent)//Not IE
{
document.attachEvent = function(){document.addEventListener(arguments[0 ].substr(2),arguments[1],arguments[2])}
}
if(!window.attachEvent)//Not IE
{
window.attachEvent = function() {window.addEventListener(arguments[0].substr(2),arguments[1],arguments[2])}
}

On the server side, as long as StringBuilder produces the above script, Then just write it out. The above just provides an idea. Of course, there are other methods. For example, I don’t use scheduled detection. I directly mount it in windows.onload and let the page automatically monitor and execute automatically. It’s not a bad idea either:), as the saying goes. All roads lead to Rome~~~~~
The above ideas come from yui, and yui has implemented a more beautiful custom MessageBox. Friends who are interested can study it together.