asp.net - How to capitalise first letter of string in javascript? -

i have created 1 form. in form there 10 textbox , 1 button. when user enters text textbox , loses focus, first letter of string should capitalised. think javascript best option this. onblur event of 10 textbox have call it. don't want call onbuttonclick event.

// javascript function

function capitalisefirstletter(string) { return string.charat(0).touppercase() + string.slice(1); }  

// cs file

page_load() { string s1 = textbox1.text.trim(); textbox1.attributes.add("onblur",capitalisefirstletter('"+s1+"')) } 

but s1 empty because i've called function in pageload(). how can handle it?

do this...

page_load() {     textbox1.attributes.add("onblur", "capitalisefirstletter('" + textbox1.clientid + "')"); } 

modify javascript function below...

function capitalisefirstletter(txtid) {     var txtstring = document.getelementbyid(txtid).value;     document.getelementbyid(txtid).value = txtstring.charat(0).touppercase() + txtstring.slice(1); }