Question

我遇到了两个函数和一个if语句的问题。我被告知函数go和postcodeChange未定义。

我也被告知flag是if flag == 1的意外标识符。

知道我哪里错了吗？谢谢。

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

未定义的函数是语法错误的直接后果 - 语法错误，函数无法理解，因此未定义。

所以，关于语法错误，我很确定if条件的括号是强制性的：

if( flag == 1)

编辑：此外，正如Wouter指出的那样，您错过了}来结束distanceCheck功能定义。还有一件事，请用;终止你的行，或准备好令人讨厌的惊喜。 ~~JavaScript会让你失望！~~

Answer 2

您忘了关闭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语句不正确：

使用

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

且distanceCheck()的功能范围不正确。

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:
}

定义函数和if语句问题

4 个答案: