Ajax combined with PHP collation review

The main function of Ajax is to implement the browser-side asynchronous access to the server: through the browser's XMLHttpRequest object to emit a small amount of data,
Interacting with the server, the server returns a small amount of data and then updates some of the client's pages.

is a request for success information

Front-End Code:

//Get TriggerLet search = document.getElementById (' Search ');//get submitted form datalet keyword = document.getElementById (' keyword ');//Post TriggerLet save = document.getElementById (' Save ');//post-submitted form dataLet Staffname = document.getElementById (' Staffname '); let Staffnumber= document.getElementById (' Staffnumber '); let Staffsex= document.getElementById (' Staffsex '); let Staffjob= document.getElementById (' Staffjob ');//Return Information Demo presentationLet SearchResult = document.getElementById (' SearchResult '); let Creatresult= document.getElementById (' Creatresult ');//GET RequestSearch.addeventlistener (' click ', () ={Let request=NewXMLHttpRequest (); Request.open (' GET ', ' service.php?number=${keyword.value} '); Request.send (NULL); Request.addeventlistener (' ReadyStateChange ', () = {    if(Request.readystate = = = 4 && request.status = = 200) {      //JSON object returned in background to JS object      //using Json.parse (Request.responsetext) When working with JSON does not perform the JS script in JSON is more secure than eval ()Let Jsondata =Json.parse (Request.responsetext); //determine if the error message requires and background convention a JSON object      if(jsondata.success) {Searchresult.innertext=jsondata.msg; } Else{Searchresult.innertext=jsondata.msg; }    }  })})//POST RequestSave.addeventlistener (' click ', () ={Let request=NewXMLHttpRequest (); Request.open (' POST ', ' service.php '); //Post must set the value of Content-type between open and sendRequest.setrequestheader ("Content-type", "application/x-www-form-urlencoded"); //construct the form data to send and then submit it with SendLet data = ' name=${staffname.value}&number=${staffnumber.value}&sex=${staffsex.value}&job=${staffjob.value} ';  Request.send (data); Request.addeventlistener (' ReadyStateChange ', () = {    if(Request.readystate = = = 4 && request.status = = 200) {      //JSON object returned in background to JS object      //using Json.parse (Request.responsetext) When working with JSON does not perform the JS script in JSON is more secure than eval ()Let Jsondata =Json.parse (Request.responsetext); //determine if the error message requires and background convention a JSON object      if(jsondata.success) {Creatresult.innertext=jsondata.msg; } Else{Creatresult.innertext=jsondata.msg; }    }  })})

Background PHP Code:

<?PHP//set page content encoding format utf-8//header ("Content-type:text/plain;charset=utf-8");//Response format plain textHeader("Content-type:application/json;charset=utf-8");//The format returned by the server is a JSON string//cross-Domain header (' access-control-allow-origin:* ');//Allow all sources to access//cross-Domain header (' Access-control-allow-method:post,get ');//Allow access to the way//header ("Content-type:text/xml;charset=utf-8");//header (" Content-type:text/html;charset=utf-8 ");//header (" Content-type:application/javascript;charset=utf-8 ");// Defines a multidimensional array that contains employee information, each employee information as an array$staff=Array  (    Array("Name" = "Hong Qi", "Number" and "101", "sex" = "male", "job" and "General manager"),Array("Name" = "Guo Jing", "number" = "102", "sex" = "male", "job" and "Development Engineer"),Array("Name" = "Huang Rong", "number" = "103", "sex" = "female", "job" and "Product manager")  );//determines if a GET request is searched; if it is a POST request, the new//$_server is a super global variable that is available in all scopes of a script without using the Global keyword//$_server["request_method "] Returns the request method used by the access pageif($_server["Request_method"]== "GET") {search ();//Search}ElseIf($_server["Request_method"]== "POST") {Create ();//New}//search Functionfunctionsearch () {//append $jsonp =$_get["callback123" when cross-domain request; Hyper Global Variables $_get and $_post are used to collect form data//detection URLs with no number field  if(!isset($_get["number"]) | |Empty($_get["Number"])){    //returns the JSON object below the client if no value is passed    Echo' {' success ': false, ' msg ': ' Please enter employee number '} '; return; }  //variables declared outside the function have global scope and can only be accessed outside of the function. Global keywords are used to access variables within functions  Global $staff; //the number field that the browser passes over  $number=$_get["Number"]; $result= ' {' success ': false, ' msg ': ' No employee found. "}‘; //cross-domain requests are changed to $result = $jsonp. ' ({"Success": false, "MSG": "No employee found.  "})‘; Iterates over $staff multidimensional arrays, finds whether an employee with a key value of number exists, modifies and returns the result if it exists  foreach($staff  as $value) {    if($value["Number"]==$number){      $result= ' {' Success ': true, ' msg ': ' Find Employee: Employee Number: '.$value["Number"]. ', Employee Name: '.$value["Name"]. ', Employee Gender: '.$value["Sex"]. ', employee Position: '.$value["Job"]. ‘"}‘;  Break; }  }  Echo $result;//return Results}//Create an employeefunctionCreate () {//Determine if the information is complete//if the name value is not found or the value is NULL, the return parameter error message is not complete  if(!isset($_post["name"]) | |Empty($_post["Name"])    ||!isset($_post["number"]) | |Empty($_post["Number"])    ||!isset($_post["Sex"]) | |Empty($_post["Sex"])    ||!isset($_post["Job"]) | |Empty($_post["Job"])){    //returns the client's JSON object when the parameter is not aligned    Echo' {' success ': false, ' msg ': ' Employee information not complete '} '; return; }  //TODO: Get post form data and save to database//otherwise prompt save successful  /*echo "Employees:". $_post["Name"]. " Information saved successfully! ";*/  Echo' {' success ': true, ' msg ': ' Employee: '.$_post["Name"]. ' Information saved successfully! "}‘;}?>

Ajax combined with PHP collation review