jQuery 如何检查函数的返回值是真还是假
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How to check the function's return value if true or false
提问by Ken
I have a function here that validate fields in a form if they are empty.
我在这里有一个函数可以验证表单中的字段是否为空。
function ValidateForm()
{
jQuery('span.error_msg').hide();
var success = true;
jQuery("#shippingF input").each(function()
{
if(jQuery(this).val()=="")
{
jQuery(this).next().show();
success = false;
}
});
return success;
}
Now I wanted to use that function here:
现在我想在这里使用该功能：
function post(url,formId) {
jQuery("#process").html('<img src="<?php echo get_bloginfo('wpurl').'/wp-content/plugins/'.basename(dirname(__FILE__)).'/images/co/ajax-loader.gif'; ?>" alt="loading" title="ajax-loader" width="16" height="16" class="alignnone size-full wp-image-134">');
jQuery.post(url, jQuery('#' + formId).serialize(), function(d) {
jQuery('html,body').animate({scrollTop: jQuery("#scrollhere").offset().top},'slow');
jQuery("#response").html('<center><p style="height:820px"><span style="color:black;font-weight:bold;font: 11px arial,verdana,sans-serif;"><b>Loading available payment getaways..</b></span><br/><img src="<?php echo get_bloginfo('wpurl').'/wp-content/plugins/'.basename(dirname(__FILE__)).'/images/co/8-1.gif'; ?>" width="220" height="19" /></p></center>');
jQuery("#response").load("<?php echo get_bloginfo('wpurl').'/wp-content/plugins/'.basename(dirname(__FILE__)).'/checkout_payment.php'; ?>", function() { Cufon.refresh(); });
jQuery("#response").attr("style","height:1030px");
});
}
I tried it and I come up with this.
我试过了，我想出了这个。
function post(url,formId) {
ValidateForm();
if(ValidateForm() == 'false') {
jQuery('html,body').animate({scrollTop: jQuery("#shippingF").offset().top},'slow');
} else {
jQuery("#process").html('<img src="<?php echo get_bloginfo('wpurl').'/wp-content/plugins/'.basename(dirname(__FILE__)).'/images/co/ajax-loader.gif'; ?>" alt="loading" title="ajax-loader" width="16" height="16" class="alignnone size-full wp-image-134">');
jQuery.post(url, jQuery('#' + formId).serialize(), function(d) {
jQuery('html,body').animate({scrollTop: jQuery("#scrollhere").offset().top},'slow');
jQuery("#response").html('<center><p style="height:820px"><span style="color:black;font-weight:bold;font: 11px arial,verdana,sans-serif;"><b>Loading available payment getaways..</b></span><br/><img src="<?php echo get_bloginfo('wpurl').'/wp-content/plugins/'.basename(dirname(__FILE__)).'/images/co/8-1.gif'; ?>" width="220" height="19" /></p></center>');
jQuery("#response").load("<?php echo get_bloginfo('wpurl').'/wp-content/plugins/'.basename(dirname(__FILE__)).'/checkout_payment.php'; ?>", function() { Cufon.refresh(); });
jQuery("#response").attr("style","height:1030px");
});
}
}
The problem is that, the validation is working.. however, .post()function runs even though there is empty field. I guess its on the if/else condition.. is there a better way to accomplish this?
问题是，验证正在工作......但是，.post()即使有空字段，函数也会运行。我猜它在 if/else 条件下......有没有更好的方法来完成这个？
Thank you.
谢谢你。
回答by Christian
false != 'false'
For good measures, put the result of validate into a variable to avoid double validation and use that in the IF statement. Like this:
对于好的措施，将验证的结果放入一个变量中以避免双重验证并在 IF 语句中使用它。像这样：
var result = ValidateForm();
if(result == false) {
...
}
回答by JDandChips
You don't need to call ValidateForm()twice, as you are above. You can just do
你不需要ValidateForm()像上面那样打电话两次。你可以做
if(!ValidateForm()){
..
} else ...
I think that will solve the issue as above it looks like your comparing true/falseto the string equivalent 'false'.
我认为这将解决上述问题，看起来您与true/false字符串等效'false'.
回答by ferry
you're comparing the result against a string ('false') not the built-in negative constant (false)
您将结果与字符串 ('false') 进行比较，而不是与内置负常数 (false) 进行比较
just use
只是使用
if(ValidateForm() == false) {
or better yet
或者更好
if(!ValidateForm()) {
also why are you calling validateForm twice?
还有你为什么要调用 validateForm 两次？
回答by lc.
Wrong syntax. You can't compare a Boolean to a string like "false" or "true". In your case, just test it's inverse:
错误的语法。您不能将布尔值与诸如“false”或“true”之类的字符串进行比较。在您的情况下，只需测试它的反向：
if(!ValidateForm()) { ...
You couldtest against the constant false, but it's rather ugly and generally frowned upon:
您可以针对常量 false 进行测试，但它相当丑陋且通常不受欢迎：
if(ValidateForm() == false) { ...
回答by Ricardo Alvaro Lohmann
ValidateFormreturns boolean,not a string.
When you do this if(ValidateForm() == 'false'), is the same of if(false == 'false'), which is not true.
ValidateForm返回boolean，而不是一个string。
当您执行此操作时if(ValidateForm() == 'false')， 与 相同if(false == 'false')，这是不正确的。
function post(url, formId) {
if(!ValidateForm()) {
// False
} else {
// True
}
}
