command to run javascript through string code example

Example 1: javascript execute string code

var theInstructions = "alert('Hello World'); var x = 100";

var F=new Function (theInstructions);

return(F());

Example 2: js execute string

var myString = "console.log('I am Batman')";
eval(myString);
//carefull ! This will execute the code, therefore 
//be careful of where/how you got this string.