定義函數和if語句問題

Question

我遇到了兩個函數和if語句的問題。我被告知功能go和postcodeChange未定義。

我也被告知flag是一個意外的標識if flag == 1。

任何想法我錯了？謝謝。

function postcodeChange(){ 
document.getElementById("goButton").onclick = distanceCheck; 
} 

function distanceCheck(){ 
var distance = document.getElementById("distance").value 
var patt1=new RegExp("^[0-9]+(\.[0-9]{1})?$"); 
var out = patt1.exec(distance); 

if (out == null) { 
    //distance is not a valid number 
    document.getElementById("distanceFlag").value = 1 
} 
else { 
    //distance is valid number 
    document.getElementById("distanceFlag").value = 0 
} 

function go(){ 
var flag = document.getElementById("distanceFlag").value 
if flag == 1 
{ 
    alert("Distance is not valid- enter a number with no more than one decimal point"); 
} 
else{ 
    popSubmit('#fa Care Provider Search Go','','0'); 
} 
} 

Answer 1

不

被定義的功能是語法錯誤的直接後果 - 與語法錯誤時，該功能不能被理解，因此不限定。

所以，關於該語法錯誤，我敢肯定，圍繞if conditonal括號是強制性的：

if(flag == 1) 

編輯：另外，作爲沃特指出，你錯過了}結束你distanceCheck功能確定指標。另一件事，請終止您的線路;或準備討厭的驚喜。 否則JavaScript會把你搞砸！

Answer 2

您忘記關閉distancecheck功能。

function postcodeChange(){ 
document.getElementById("goButton").onclick = distanceCheck; 
} 

function distanceCheck(){ 
var distance = document.getElementById("distance").value 
var patt1=new RegExp("^[0-9]+(\.[0-9]{1})?$"); 
var out = patt1.exec(distance); 

if (out == null) { 
    //distance is not a valid number 
    document.getElementById("distanceFlag").value = 1 
} 
else { 
    //distance is valid number 
    document.getElementById("distanceFlag").value = 0 
} 
} 

function go(){ 
var flag = document.getElementById("distanceFlag").value 
if flag == 1 
{ 
    alert("Distance is not valid- enter a number with no more than one decimal point"); 
} 
else{ 
    popSubmit('#fa Care Provider Search Go','','0'); 
} 
} 

Answer 3

if語句是不正確的：

使用

if(flag==1){//your statement} 
else {//your statement} 

和distanceCheck()功能範圍不正確。

Answer 4

function postcodeChange(){ 
    document.getElementById("goButton").onclick = distanceCheck; 
} 

function distanceCheck() { 
    var distance = document.getElementById("distance").value 
    var patt1=new RegExp("^[0-9]+(\.[0-9]{1})?$"); 
    var out = patt1.exec(distance); 

    if (out == null) { 
     //distance is not a valid number 
     document.getElementById("distanceFlag").value = 1 
    } 
    else { 
     //distance is valid number 
     document.getElementById("distanceFlag").value = 0 
    } 

// } 
// should we close the function here ? 
// Or is `go` a function inside the function `distanceCheck`: 

    function go(){ 
     var flag = document.getElementById("distanceFlag").value 
     if (flag == 1) { // <-- Use parantes' when dealing with if-statements 
      alert("Distance is not valid- enter a number with no more than one decimal point"); 
     } 
     else { 
     popSubmit('#fa Care Provider Search Go','','0'); 
     } 
    } 
// Nether the less you will need to close the function scope somewhere if not above then down here: 
}