Javascript learning experience

I have been pondering javascript For the past few days, but I have never had any practical experience. Now I think there are a lot of practical errors. I will continue to summarize the errors in the future. The key is to reduce the debugging time, cainiao: 1. js usually has a local error, and the following functions won't continue to be executed (originally... syntaxHighlighter. all (); I have been thinking about javascript For the past few days. I have never had any practical experience. Now I think there are a lot of practical errors. I will keep summing up the errors in the future. The key is to reduce the debugging time, cainiao:
1. js usually has a local error, and the following functions won't continue to be executed (something that I thought was normal, ...)
2. Why should a parameter change be added behind the requested servlet when an open () request is sent to the server to inform the server that this is a new request ??? Otherwise, the request fails in IE8.
Var bojingNum = 0;
// Define a variable to store the xmlHttpRequest object
Var xmlHttp = null;
// This function is used to create an xmlHttpRequest object.
Function createXMLHttpRequest ()
{
If (window. ActiveXObject) // The ActiveXObject object is a control provided by IE browser, so some online banking only supports the IE browser of this control.
{
XmlHttp = new ActiveXObject ("Microsoft. XMLHTTP"); // The object generated by the IE browser

} Else if (window. XMLHttpRequest) // other browsers except IE
{
XmlHttp = new XMLHttpRequest ();
}
}
// This is a method for refreshing the Statistical Chart through ajax
Function autoFlush ()
{
// Create date variable time variable
Var tempTime = new Date ();
Var tempParameter = tempTime. getTime ();
// Create an xmlHttpRequest object
CreateXMLHttpRequest ();
If (xmlHttp! = Null)
{
// Place a time parameter here to let the server know that this is a new request
XmlHttp. open ("GET", "SerialDataSvt? Tmd = "+ tempParameter );
// Bind the status trigger to a function
XmlHttp. onreadystatechange = processor;

// Send the request
XmlHttp. send (null );
}


}
// Process the xml document returned from the server
Function processor ()
{
// Define a variable to store the results returned by the slave server
Var result;
If (xmlHttp. readyState = 4) // if the response is complete
{
If (xmlHttp. status = 200) // if the returned result is successful
{

// Retrieve the child nodes of all counter labels of the xml document returned by the server
Result = xmlHttp. responseXML. getElementsByTagName ("data"); // alert (result );

// Parse the data in xml and update the Statistical Chart status

For (var I = 0; I <result. length; I ++)
{
// Used to update the statistics image status
Var id = result [I]. getAttribute ("id"); // alert (id );
Var dir = result [I]. getAttribute ("dir"); // alert (dir );

Var datas = xmlHttp. responseXML. getElementsByTagName ("dataContent") [0]. childNodes [0]. nodeValue;
Var addTime = xmlHttp. responseXML. getElementsByTagName ("addTime") [0]. childNodes [0]. nodeValue;


If (datas. substring (17,18) = "1 ")
{
Document. getElementById ("yujing" + (I + 1). innerHTML =" Alarming";
Document. getElementById ("yujingPic" + (I + 1). style. display = 'block ';
BojingNum ++;
Document. getElementById ("yujingNum" + (I + 1). innerHTML = "alert times:" + bojingNum;
}
Else
{
Document. getElementById ("yujing" + (I + 1). innerHTML = "no alert ";
Document. getElementById ("yujingPic" + (I + 1). style. display = 'none ';
}
Document. getElementById ("n_nodeID" + I). innerHTML = id + dir;
Document. getElementById ("n_nodeData" + I). innerHTML = datas;
Document. getElementById ("n_nodeTime" + I). innerHTML = addTime;

Document. getElementById ("s_nodeID" + I). innerHTML = id + dir;
Document. getElementById ("s_nodeData" + I). innerHTML = datas;
Document. getElementById ("s_nodeTime" + I). innerHTML = addTime;

Document. getElementById ("e_nodeID" + I). innerHTML = id + dir;
Document. getElementById ("e_nodeData" + I). innerHTML = datas;
Document. getElementById ("e_nodeTime" + I). innerHTML = addTime;

Document. getElementById ("w_nodeID" + I). innerHTML = id + dir;
Document. getElementById ("w_nodeData" + I). innerHTML = datas;
Document. getElementById ("w_nodeTime" + I). innerHTML = addTime;

}
}
}
}
// Execute the autoFlush method once every second.
SetInterval (FIG, 2000 );