JS is Dynamic

//Compilation and execution happen together.varpropMap={val:"value",html:"innerHTML"};for(varfnNameinpropMap){$.prototype[fnName]=(function(prop){returnfunction(){returnthis[prop];}})(propMap[fnName]);}

JS is Weakly Typed

//Type associated with value, not variable.vara=1;a="one";a=[1];a={one:1};

JS has 1st Class Functions

//Treat like any objectvarsquare=function(x){returnx*x},//createmult=function(f1,f2){// Returnreturnfunction(n){returnf1(n)*f2(n);}},bigF=mult(square,square),// ARGvalue=bigF(2);// 16

JS is Prototype Based