JavaScript AND（&&）运算符给出了非法字符错误，然后是另一个错误

Question

我正在构建一个代码块，并遇到了一个问题，这使我很好奇为什么为什么＆符不会从WordPress文本编辑器视图进行编码。这段代码按预期工作，当通过文本编辑器直接嵌入到页面中时，它会向我发出警报：

// This code works as expected
<script>
jQuery(document).ready(function() {
    if (jQuery('select[name=idx-q-PropertyTypes]:first').val()=='') {alert ('it exists');} else {alert ('cant find it');} 
    jQuery('.dsidx-resp-area-submit input').click(function(e){
        alert ("you clicked it");
        if (jQuery('select[name=idx-q-PropertyTypes]:first').val()=='') {
            alert ('There were no search parameters.');
            e.preventDefault();
        }
    });
});
</script>

我想做的下一件事是检查条件并发。所以我将代码更改为此：

// This code gives errors 
<script>
jQuery(document).ready(function() {
    if (jQuery('select[name=idx-q-PropertyTypes]:first').val()=='') {alert ('it exists');} else {alert ('cant find it');} 
    jQuery('.dsidx-resp-area-submit input').click(function(e){
        alert ("you clicked it");
    if (
        jQuery('select[name=idx-q-PropertyTypes]:first').val()=='' &&
        jQuery('select[name=idx-q-Cities]:first').val()=='' &&
        jQuery('input[name=idx-q-PriceMin]:first').val()=='' &&
        jQuery('input[name=idx-q-PriceMax]:first').val()=='' &&
        jQuery('select[name=idx-q-BedsMin]:first').val()=='' &&
        jQuery('select[name=idx-q-BathsMin]:first').val()=='' &&
        jQuery('input[name=idx-q-ImprovedSqFtMin]:first').val()==''
    ) {
        alert ('There were no search parameters.');
            e.preventDefault();
        }
    });
});
</script>

The error I got at first is that I had used an illegal character. When I looked up where in the debugger, it was the double ampersands. They showed up as &. So, next I tried replacing all of them with &, which didn't work. After replacing them like that, I got a new error saying that the conditional statement was missing a closing parenthesis. To fix that, I tried add a parenthesis at the end, enclosing each condition in a set of parentheses, and writing the whole condition on one line, each in turn, none of which worked. I also plugged it into a fiddle as this question建议，但这也不起作用。像这样替换它们之后，我收到一个新错误，说条件语句缺少右括号。为了解决这个问题，我尝试在最后添加一个括号，将每个条件括在一组括号中，然后将整个条件写在一行上，然后依次写成一行，但都不起作用。

当我将链接作为外部文件链接到脚本时，“＆”号可以正确编码，并且整个脚本都可以工作。有谁知道为什么会这样，如果我想像最初尝试的那样嵌入脚本，是否有办法解决这个问题？

Answer 1

因此，您需要将脚本放在 CDATA 中，但如果您不想这样做，如果您不想更改代码，则可以这样做。

var val=jQuery('select[name=idx-q-PropertyTypes]:first').val() +
    jQuery('select[name=idx-q-Cities]:first').val() +
    jQuery('input[name=idx-q-PriceMin]:first').val() +
    jQuery('input[name=idx-q-PriceMax]:first').val() +
    jQuery('select[name=idx-q-BedsMin]:first').val() +
    jQuery('select[name=idx-q-BathsMin]:first').val() +
    jQuery('input[name=idx-q-ImprovedSqFtMin]:first').val();
if (val=="") ...

选择：

var isEmpty = $('[name^=idx-q]:first')
            .filter(
              function() { 
                return $(this).val() != ""; 
              }
            )
            .length==0;