alert a variable value

Question

How do I display the value of a variable in javascript in an alert box   For example I ve got a variable x 100 and alert x  isn t working   the script used in grease monkey is here  var inputs   document getElementsByTagName  input     var new  for  i 0  i lt inputs length  i        if  inputs i  getAttribute  name       ans        new inputs i  getAttribute  value      alert new

User · Answer

var input val document getElementById  my variable   for  i 0  i lt input val length  i      xx   input val i     if  xx name     ans            new   xx value      alert new

User · Answer

A couple of things    You can t use new as a variable name  it s a reserved word  On input elements  you can just use the value property directly  you don t have to go through getAttribute  The attribute is  reflected  as a property  Same for name    So   var inputs  input  newValue  i   inputs   document getElementsByTagName  input    for  i 0  i lt inputs length  i          input   inputs i       if  input name     ans                newValue   input value          alert newValue

User · Answer

If you re using greasemonkey  it s possible the page isn t ready for the javascript yet  You may need to use window onReady   var inputs   function doThisWhenReady         inputs   document getElementsByTagName  input           Other code here       window onReady   doThisWhenReady

User · Answer

Note  while the above answers are correct  if you want  you can do something like   alert  The variable named x1 has value       x1

User · Answer

show alert box with use variable with message   lt script gt    document  ready function     var total   30   alert  your total is     total   rs         lt  script gt

User · Answer

See with the help of the following example if you can use literals and     sign in your case      function doHomework subject               alert   Starting my   subject  homework                  doHomework  maths

User · Answer

If I m understanding your question and code correctly  then I want to first mention three things before sharing my code version of a solution  First  for both name and value you probably shouldn t be using the getAttribute   method because they are  themselves  properties of  the variable named  inputs  at a given index of i   Secondly  the variable that you are trying to alert is one of a select handful of terms in JavaScript that are designated as  reserved keywords  or simply  reserved words   As you can see in on this list  on the link   new is clearly a reserved word in JS and should never be used as a variable name   For more information  simply google  reserved words in JavaScript   Third and finally  in your alert statement itself  you neglected to include a semicolon   That and that alone can sometimes be enough for your code not to run as expected    Aside  I m not saying this as advice but more as observation  JavaScript will almost always forgive and allow having too many and or unnecessary semicolons  but generally JavaScript is also equally if not moreso merciless if when missing  any of the  necessary  required semicolons  Therefore  best practice is  of course  to add the semicolons only at all of the required points and exclude them in all other circumstances  But practically speaking  if in doubt  it probably will not hurt things by adding including an extra one but will hurt by ignoring a mandatory one  General rules are all declarations and assignments end with a semicolon  such as variable assignments  alerts  console log statements  etc   but most all expressions do not  such as for loops  while loops  function expressions Just Saying   But I digress        function whenWindowIsReady             var inputs   document getElementsByTagName  input            var lengthOfInputs   inputs length     this is for optimization         for  var i   0  i  lt  lengthOfInputs  i                  if  inputs i  name      ans                        var ansIsName   inputs i  value                  alert ansIsName                                      window onReady   whenWindowIsReady      PS  You used a double assignment operator in your conditional statement  and in this case it doesn t matter since you are comparing Strings  but generally I believe the triple assignment operator is the way to go and is more accurate as that would check if the values are EQUIVALENT WITHOUT TYPE CONVERSION  which can be very important for other instances of comparisons  so it s important to point out  For example  1   1  and 0  false are both true  when usually you d want those to return false since the value on the left was not the same as the value on the right  without type conversion  but 1    1  and 0   false are both false as you d expect because the triple operator doesn t rely on type conversion when making comparisons  Keep that in mind for the future

[javascript] alert a variable value

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