jquery script for inserting and deleting text
I suppose you're talking about these 3 JSLint warnings:
Combine this with the previous 'var' statement.
  var interval = 300 - Math.random() * 100;

Combine this with the previous 'var' statement.
  var interval = 3000;

Do not use 'new' for side effects.
      new Typing(this, toType, interval);

The first 2 are suggestions to combine multiple var declarations into one. For example, instead of:

var x = 3;
var y = 4;


The suggestion is to do like this instead:
var x = 3, y = 4;

The 3rd one is about instantiating something without storing the reference somewhere. This page explains why this is not recommended, in particular:

By not assigning the return value of a constructor to something you will lose the reference to that instance. Generally, by constructing an instance you would want to keep that reference, whether to use again later or for &quot;internal&quot; use as part of a comparison. What's the point of constructing something you are going to throw away as soon as it's been created?
If you have a constructor function that performs work beyond simply setting up an instance, and you are calling that constructor just for these &quot;side effects&quot;, consider reworking your code to allow you to call the function normally, without the new operator.

Personally I disagree with the suggestion to combine the var statements, but agree with the 3rd warning.