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(1) Bind The onclick event of the DOM element to the Method
Dom. onclick = function () {otherfunctiong ()};
When using js to define the onclick-triggered function, you must use an anonymous function to enclose the called function. Otherwise, the called function will be executed directly.
Example:
Correct:
Tempa. onclick = function () {getinfo (residentinfo. residentid )};
Error:
Tempa. onclick = getinfo (residentinfo. residentid );
This write method will directly getinfo (residentinfo. residentid) before the onclick event occurs );
(2) functiona () callback function B after execution
Correct syntax:
FunctionInitinput (callback ){VaRAJ =NewAjax ();VaRUrl = "../addedhandlers/residentinfo. ashx? Type = getallbindinfo"; AJ. Post (URL,Null,False,Function(Info ){..........If(Callback! =Null) {Callback ();})};} Initinput (Function() {Getinfo (ID,True);});
Incorrect syntax:
Initinput (getinfo (ID,True));
Cause of error: the getinfo method is executed first.
(3) Events bound to DOM elements in a loop
For (VAR I = 0; I <n; I ++) {var resiidnode = resibriefs [I]. selectsinglenode ("residentid"); var residentid = resiidnode. text; var resinamenode = resibriefs [I]. selectsinglenode ("residentname"); If (resinamenode! = NULL) {var residentname = resinamenode. Text; var httpstr = ""; if (resirelationnode! = NULL & resirelationnode. Text! = "") {If (resirelationnode. childnodes [0]. nodevalue = "") {var Tempa = document. createelement ("A"); Tempa. style. fontweight = "bold"; Tempa. setattribute ("ID", residentid); // Tempa. onclick = function () {alert (residentid); getinfo (residentid);} // The parameter bound to all DOM elements is the last value of.
Tempa. onclick = function () {getinfo (this. getattribute ("ID");} // Tempa is written correctly. appendchild (document. createtextnode (residentname); document. getelementbyid ("peoplelist "). appendchild (Tempa );}
}
}
}
2. keyboard input
<Body onkeypress = "bodykeypressed ()">
/* Body keypressed
*/
Function bodykeypressed (){
If (event. keycode = 13) {checkusrpsw ();}
}
Iii. Execution textCode
Function; EVAL
<! Doctype HTML public "-// W3C // dtd xhtml 1.0 transitional // en" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <HTML xmlns = "http://www.w3.org/1999/xhtml"> Function Execute (){ /* Method 1 var sscript = "(function () {" + document. getelementbyid ("txscript "). value + "}) ()"; // execute the function var func = new function (sscript); // The last parameter of the function is the function body try {func ();} by default ();} */ // Method 2 VaR Sscript = Document. getelementbyid ("txscript"). Value; Try {Eval (sscript );} Catch (E) {alert (E. Description );}} </SCRIPT>
Iii. How to Avoid sysfader errors in JS asynchronous callback Functions
Background: You often need to bind the callback function to an anonymous function. If the binding statement does not take effect, the sysfader is triggered after the method is executed.
Example: 3DCommunitySystem: updates the room location.
Solution: Before executing the Asynchronous Method (createpoint), check whether the client callback function book is correctly bound.
VaR type = obj. getattribute ("litype"); top. usearth. event. onpoiclicked = top. emptypoiclicked; // click prohibited effect to prevent sysfader from adding top points. usearth. event. oncreatepoint = function (pval ){....................... vaR endstr = "the event is well set";}; top. usearth. shapecreator. clear (); try {If (top. usearth. event. oncreatepoint. tostring (). indexof ('the event is well set ')! =-1) {// check whether the oncreatepoint is bound to a normal top. usearth. shapecreator. createpoint () ;}else {Throw "location moving failed, please move again" ;}} catch (e) {alert (E); return ;}
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