/** * @author Michael.Howlett */ /* * runOnLoad.js: portable registration for onload event handlers. * * This module defines a single runOnLoad() function for portably registering * functions that can be safely invoked only when the document is fully loaded * and the DOM is available. * * Functions registered with runOnLoad() will not be passed any arguments when * invoked. They will not be invoked as a method of any meaningful object, and * the this keyword should not be used. Functions registered with runOnLoad() * will be invoked in the order in which they were registered. There is no * way to deregister a function once it has been passed to runOnLoad(). * * In old browsers that do not support addEventListener() or attachEvent(), * this function relies on the DOM Level 0 window.onload property and will not * work correctly when used in documents that set the onload attribute * of their or tags. */ function runOnLoad(f) { if (runOnLoad.loaded) f(); // If already loaded, just invoke f() now. else runOnLoad.funcs.push(f); // Otherwise, store it for later } runOnLoad.funcs = []; // The array of functions to call when the document loads runOnLoad.loaded = false; // The functions have not been run yet. // Run all registered functions in the order in which they were registered. // It is safe to call runOnLoad.run() more than once: invocations after the // first do nothing. It is safe for an initialization function to call // runOnLoad() to register another function. runOnLoad.run = function() { if (runOnLoad.loaded) return; // If we've already run, do nothing for(var i = 0; i < runOnLoad.funcs.length; i++) { try { runOnLoad.funcs[i](); } catch(e) { /* An exception in one function shouldn't stop the rest */ } } runOnLoad.loaded = true; // Remember that we've already run once. delete runOnLoad.funcs; // But don't remember the functions themselves. delete runOnLoad.run; // And forget about this function too! }; // Register runOnLoad.run() as the onload event handler for the window if (window.addEventListener) window.addEventListener("load", runOnLoad.run, false); else if (window.attachEvent) window.attachEvent("onload", runOnLoad.run); else window.onload = runOnLoad.run;