Snippet for clear JS console.

dev_console.js

// taken from http://stackoverflow.com/questions/3011600/clear-javascript-console-in-google-chrome

if (typeof console._commandLineAPI !== 'undefined') {
    console.API = console._commandLineAPI;
} else if (typeof console._inspectorCommandLineAPI !== 'undefined') {
    console.API = console._inspectorCommandLineAPI;
} else if (typeof console.clear !== 'undefined') {
    console.API = console;
}

console.API.clear();