startswith function in javascript

[nakku]

my form has a textbox that accepts input from the user. Now i want my javascript to check the value from the textbox if it starts with any specified characters. How can i do this in javascript? please help...

[r035198x]

my form has a textbox that accepts input from the user. Now i want my javascript to check the value from the textbox if it starts with any specified characters. How can i do this in javascript? please help...

You can use a regular expression for it.

[acoder]

If you know about prototype and the ability to add methods to the String object directly, try this:

String.prototype.startsWith = function(str) {return (this.match(”^”+str)==str)}

Then use as a normal method of the String object.

[mrhoo]

Both r0's and acoder's solutions are good. I combine them-

String.prototype.begin= function(c){
return (c)? (this.search(c)== 0): this.charAt(0);
}

You can pass nothing, and get the first character,
or a string or regular expression, and get a true or false if the string starts with the argument passed.