About constant equals (= = =) and non-constant Equals (!==) _javascript tips

In looking at Ext source code, encountered "= = =" and "!==" of the writing, temporarily puzzled, in the group of information, only to know what they represent the meaning.
Oh, it seems to have a network is really convenient:
Reference
• constant equals (= = = = Check whether two operands are the same, that is, check that the values of operands that do not have data type conversions are equal.)
• Non-constant Equals (!==): Check that the value of two operands is not the same as before data conversion.
The following is an excerpt from the discussion chat record:

Maple Rock 09:24:01
if (index!==-1) {
...
}

What does that mean? Who knows?
Road Pedestrian 09:26:32
= = = = Constant equals.
Road Pedestrian 09:26:41
!== is not constant equal to.
Maple Rock 09:33:58
Oh, according to the road pedestrian said "constant equals" search under:

3. Use constant equals and non-constant equals operators (= = = and!===)
1 Strictly compare the value of two variables is equal, do not do any conversion work, such as 2=== "2" is not tenable, return false
Maple Rock 09:34:13
<script type= "Text/javascript" >
<!--
Alert (2== "2");
Alert (2=== "2");
Alert (2!== "2");
-->
</script>
Maple Rock 09:36:32
Hey, this detailed point:
• constant equals (= = = = Check whether two operands are the same, that is, check that the values of operands that do not have data type conversions are equal.)
• Non-constant Equals (!==): Check that the value of two operands is not the same as before data conversion.
Road Pedestrian 09:39:41
What does the IF (index!==1) mean ... Maple Rock??
Maple Rock 09:43:04
Index!==1
Equivalent:
! (index===1)
Maple Rock 09:43:10
It's supposed to be like this.
Maple Rock 09:43:18
I'll give it a try.
Maple Rock 09:44:07
<script type= "Text/javascript" >
<!--
var a = (2!== "2");
var B =! (2=== "2");
Alert (A = = = B);
-->
</script>
Maple Rock 09:44:40
The comparison of 2=== "2" also requires the same data type
Maple Rock 09:44:45
Before returning to the true
Z 09:49:30
= = = This is the case
Z 09:49:44
If the two values have different types, they are not identical.
Z 09:51:52
= = should be to convert two numbers to char and compare values
= = = Whether to compare the same type first
Maple Rock 09:54:42
Tested it, and it did.
<script type= "Text/javascript" >
<!--
var O1 = {A: "a"};
var O2 = o1.tostring ();
alert (O1==O2);
alert (O1===O2);
-->
</script>