Label statement:
In JavaScript, any statements can add a tag, the program jumps to set paths in a complex structure.
Syntax: label: statements statements ---- Statement List
Label label is any legal identifier, but you can not use a reserved word.
A tag name variable name may duplicate names
A tag name tag attribute names belong to the category, must be unique;
After the break keyword can be followed by a label name to indicate the program to jump to the termination position. Syntax: break label;
break statement statements and label bound to use only the inner nested structure.
Computing performance:
1. The look-up table method can eliminate all conditional,
2. FIELD logical mapping table method for forming a key and a value
3.switch apply to each key needs a unique action or series of actions occasions.