JavaScript函数发送字符串但接收布尔值

Question

I am facing the unexpected behavior of javascript function. Im an passing the ID of a field as string to function but it is receiving as bool value. Please help the code is below.

Function

 function page_smooth_scroll(target_id) { if (target_id =! null) { $j('html, body').animate({ scrollTop: $j("#" + target_id).offset().top - 120 }, 500); } } 

calling function

 function validatePassword(){ var validPassword = false; var pwd = $j("#Password").val().trim(); var cfmPwd = $j("#ConfirmPassword").val().trim(); if((pwd == "") || (cfmPwd == "")){ $j("#ConfirmPassword").addClass("invalidPwd").nextAll("ul.err-msg").html("<li>Please enter Password</li>"); //here id is passed as string page_smooth_scroll("ConfirmPassword"); validPassword = false; } else{ $j("#ConfirmPassword").removeClass("invalidPwd").nextAll("ul.err-msg").empty(); if(pwd != cfmPwd){ $j("#ConfirmPassword").addClass("invalidPwd").nextAll("ul.err-msg").html("<li>Password does not match</li>"); //here id is passed as string page_smooth_scroll("ConfirmPassword"); validPassword = false; } else{ $j("#ConfirmPassword").removeClass("invalidPwd").nextAll("ul.err-msg").empty(); validPassword = true; } } return validPassword; } 

the image is below while debugging passing string

receiving bool

Answer 1

if (target_id =! null) {

I think you mean a != b

Because a=!b means a = !b which means "assign the opposite boolean value", which will indeed turn anything into a boolean.

Next time if you think a function is "receiving a boolean", make sure to debug the value before running any statements. I'm sure it's still a string when going into the function.