xmlHttp.responseText不從json webservice返回數據

Question

我想從json webservice中檢索數據。

if (xmlHttp.status == 200 || xmlHttp.status == 0) 
     { 
      var result = xmlHttp.responseText; 
      json = eval("(" + result + ")"); 
     } 

我「米卻一無所獲的VAR的結果。當我更換包含JSON對象的文本文件的Web服務，那麼我可以檢索JSON對象的responseText。請首先幫助

Answer 1

第一件事...... 永遠，永遠，永遠使用eval *。eval =邪惡。

如何使用GET與AJAX ...

try { 
    http = new ActiveXObject("Msxml2.XMLHTTP"); 
} catch (e1) { 
    try { 
     http = new ActiveXObject("Microsoft.XMLHTTP"); 
    } catch (e2) { 
     this.xmlhttp = null; 
    } 
} 
var url = "/uri/of/web-service?val1=Laura&val2=Linney" + Math.random(); 
var params = "val1=Laura&val2=Linney"; 
http.open("GET", url, true); 

http.onreadystatechange = function() { 
    if(http.readyState == 4 && http.status == 200) { 
     // we have a response and this is where we do something with it 
     json = JSON.parse(http.responseText); 
    } 
} 
http.send(); 

如何使用POST與AJAX ...

try { 
    http = new ActiveXObject("Msxml2.XMLHTTP"); 
} catch (e1) { 
    try { 
     http = new ActiveXObject("Microsoft.XMLHTTP"); 
    } catch (e2) { 
     this.xmlhttp = null; 
    } 
} 
var url = "/uri/of/web-service"; 
var params = "val1=Laura&val2=Linney"; 
http.open("POST", url, true); 

http.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); 
http.setRequestHeader("Content-length", params.length); 
http.setRequestHeader("Connection", "close"); 

http.onreadystatechange = function() { 
    if(http.readyState == 4 && http.status == 200) { 
     // we have a response and this is where we do something with it 
     json = JSON.parse(http.responseText); 
    } 
} 
http.send(params);