Posted: | Categories: JavaScript, Programming
Here’s a little JavaScript function that disables all form elements:
function disableElements(formName) {
var fm = document.forms[formName];
for(var i = 0; i < fm.elements.length; ++i) {
fm.elements[i].disabled = true;
}
}As you may have noticed the only parameter you need to pass is the form name.
Read more...Posted: | Categories: Database, Java, Programming | Tags: ResultSet, ResultSetMetaData
In Java it is possible to retrieve the number of columns of a ResultSet dinamically, thanks to the ResultSetMetaData
class. Here’s an example:
// Here you get the conn object. E.g.:
// Connection conn = DriverManager.getConnection(...);
Statement st = conn.createStatement();
ResultSet rs = st.executeQuery("SELECT * FROM your_table");
ResultSetMetaData rsmd = rs.getMetaData();
int numCols = rsmd.getColumnCount();
System.out.println("Number of columns in your_table: " + numCols);The previous code retrieves and displays the number of columns of your_table.
Posted: | Categories: JavaScript, Programming | Tags: RegExp
There are whole books about regular expressions so this post shouldn’t be intended as an exhaustive resource on the subject. It just shows how to extract a substring from a string using regular expressions in JavaScript so it must be considered just a tip not a tutorial on RegExp. Look at the following example:
var str = "https://www.alessandrolacava.com/?code=ALE69";
var regex = /code=(w+)&?/;
var results = regex.exec(str);
if(!results){
alert("no match");
}
else{
// first group
alert(results[1]);
}The previous code extracts the string that follows the code= part of str. That string is captured in the first group. of the RegExp, that’s why I use results[1] to display it. When you utilise groups–through the use of parenthesis ()–you can refer to them using indices, starting from 1. Indeed, at the index 0 you find the whole match. In the previous example, results[0] is equal to code=ALE69
Posted: | Categories: JavaScript, Programming | Tags: Timestamp
Many sources use the term timestamp to refer specifically to Unix time, the number of seconds since 00:00:00 UTC on January 1, 1970. In JavaScript you can use the built-in object Date to compute this timestamp. Here follows an example:
var ts = Date.UTC('2007', '09', '28') / 1000;
alert(ts);The previous code displays an alert with the number of seconds between 00:00:00 UTC on January 1, 1970 and 00:00:00 UTC on October 28, 2007.
Read more...